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91-511: (Redirected from Star Sapphire ) Star sapphire or Star Sapphire may refer to: Star sapphire, a type of sapphire gemstone that exhibits a star-like reflection of light (an asterism) The Armstrong Siddeley Star Sapphire , a British car manufactured from 1958 to 1960 Star Sapphire (DC Comics character) , the name of several fictional supervillains in DC Comics publications Star Sapphire,

182-468: A certificate from an independent gemological laboratory attesting to "no evidence of heat treatment". Yogo sapphires do not need heat treating because their cornflower blue color is attractive out of the ground; they are generally free of inclusions , and have high uniform clarity. When Intergem Limited began marketing the Yogo in the 1980s as the world's only guaranteed untreated sapphire, heat treatment

273-399: A dominant red body color. This is generally caused by traces of chromium (Cr ) substituting for the (Al ) ion in the corundum structure. The color can be modified by both iron and trapped hole color centers. Unlike localized ("intra-atomic") absorption of light, which causes color for chromium and vanadium impurities, blue color in sapphires comes from intervalence charge transfer, which is

364-438: A few well-defined directions. Scoring the wafer along cleavage planes allows it to be easily diced into individual chips (" dies ") so that the billions of individual circuit elements on an average wafer can be separated into many individual circuits. Wafers under 200 mm diameter have flats cut into one or more sides indicating the crystallographic planes of the wafer (usually a {110} face). In earlier-generation wafers

455-529: A fictional character from the Touhou Project series of video games Star Sapphire, Forbidden Planet Robby the Robot - " Star Sapphires take a week to crystalize properly. " Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title Star sapphire . If an internal link led you here, you may wish to change the link to point directly to

546-480: A group consisting of New York State ( SUNY Poly / College of Nanoscale Science and Engineering (CNSE)), Intel, TSMC, Samsung, IBM, Globalfoundries and Nikon companies has formed a public-private partnership called Global 450mm Consortium (G450C, similar to SEMATECH ) who made a 5-year plan (expiring in 2016) to develop a "cost effective wafer fabrication infrastructure, equipment prototypes and tools to enable coordinated industry transition to 450mm wafer level". In

637-410: A lot of strain due to the high thermal gradient between the flame and surrounding air. To release this strain, the now finger-shaped crystal will be tapped with a chisel to split it into two halves. Due to the vertical layered growth of the crystal and the curved upper growth surface (which starts from a drop), the crystals will display curved growth lines following the top surface of the boule. This

728-432: A metric ton) and take 2–4 times longer to cool, and the process time will be double. All told, the development of 450 mm wafers requires significant engineering, time, and cost to overcome. In order to minimize the cost per die , manufacturers wish to maximize the number of dies that can be made from a single wafer; dies always have a square or rectangular shape due to the constraint of wafer dicing . In general, this

819-567: A pair of flats at different angles additionally conveyed the doping type (see illustration for conventions). Wafers of 200 mm diameter and above use a single small notch to convey wafer orientation, with no visual indication of doping type. 450 mm wafers are notchless, relying on a laser scribed structure on the wafer surface for orientation. Silicon wafers are generally not 100% pure silicon, but are instead formed with an initial impurity doping concentration between 10 and 10 atoms per cm of boron , phosphorus , arsenic , or antimony which

910-475: A purity of 99.9999999% ( 9N ) or higher. One process for forming crystalline wafers is known as the Czochralski method , invented by Polish chemist Jan Czochralski . In this process, a cylindrical ingot of high purity monocrystalline semiconductor, such as silicon or germanium , called a boule , is formed by pulling a seed crystal from a melt . Donor impurity atoms, such as boron or phosphorus in

1001-400: A rate of 1 to 100 mm per hour. The alumina crystallizes on the end, creating long carrot-shaped boules of large size up to 200 kg in mass. Synthetic sapphire is also produced industrially from agglomerated aluminum oxide, sintered and fused (such as by hot isostatic pressing ) in an inert atmosphere, yielding a transparent but slightly porous polycrystalline product. In 2003,

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1092-503: A respected laboratory such as GIA , Lotus Gemology , or SSEF , is often required by buyers before they will make a purchase. Sapphires in colors other than blue are called "fancy" sapphires. "Parti sapphire" is used for multicolor stones with zoning of different colors (hues), but not different shades. Fancy sapphires are found in yellow, orange, green, brown, purple, violet, and practically any other hue. Gemstone color can be described in terms of hue , saturation , and tone . Hue

1183-496: A silicon wafer of the same diameter. Wafer thickness is determined by the mechanical strength of the material used; the wafer must be thick enough to support its own weight without cracking during handling. The tabulated thicknesses relate to when that process was introduced, and are not necessarily correct currently, for example the IBM BiCMOS7WL process is on 8-inch wafers, but these are only 200 μm thick. The weight of

1274-417: A variety of shades. Corundum that contains extremely low levels of chromophores is near colorless. Completely colorless corundum generally does not exist in nature. If trace amounts of iron are present, a very pale yellow to green color may be seen. However, if both titanium and iron impurities are present together, and in the correct valence states, the result is a blue color. Intervalence charge transfer

1365-443: A wafer exists commercially, does not imply in any way that processing equipment to produce chips on that wafer exists, indeed such equipment tends to lag development until paying end customer demand materializes. Even after equipment is developed (years), it can take further years for fabs to figure out how to use the machines productively. A unit of wafer fabrication step, such as an etch step, can produce more chips proportional to

1456-409: Is 100–200 mm square and the thickness is 100–500 μm. Electronics use wafer sizes from 100 to 450 mm diameter. The largest wafers made have a diameter of 450 mm, but are not yet in general use. Wafers are cleaned with weak acids to remove unwanted particles. There are several standard cleaning procedures to make sure the surface of a silicon wafer contains no contamination. One of

1547-399: Is a computationally complex problem with no analytical solution, dependent on both the area of the dies as well as their aspect ratio (square or rectangular) and other considerations such as the width of the scribeline or saw lane, and additional space occupied by alignment and test structures . (By simplifying the problem so that the scribeline and saw lane are both zero-width, the wafer

1638-442: Is a process that produces a strong colored appearance at a low percentage of impurity. While at least 1% chromium must be present in corundum before the deep red ruby color is seen, sapphire blue is apparent with the presence of only 0.01% of titanium and iron. Colorless sapphires, which are uncommon in nature, were once used as diamond substitutes in jewelry, and are presently used as accent stones. The most complete description of

1729-459: Is a specific change in energy for the electron, and electromagnetic energy is absorbed. The wavelength of the energy absorbed corresponds to yellow light. When this light is subtracted from incident white light, the complementary color blue results. Sometimes when atomic spacing is different in different directions, there is resulting blue-green dichroism . Purple sapphires contain trace amounts of chromium and iron plus titanium and come in

1820-486: Is a type of sapphire that exhibits a star-like phenomenon known as asterism ; red stones are known as "star rubies". Star sapphires contain intersecting needle-like inclusions following the underlying crystal structure that causes the appearance of a six-rayed "star"-shaped pattern when viewed with a single overhead light source. The inclusion is often the mineral rutile , a mineral composed primarily of titanium dioxide . The stones are cut en cabochon , typically with

1911-439: Is added to the flame, causing it to burn slightly hotter. This expands the growing crystal laterally. At the same time, the pedestal is lowered at the same rate that the crystal grows vertically. The alumina in the flame is slowly deposited, creating a teardrop shaped " boule " of sapphire material. This step is continued until the desired size is reached, the flame is shut off and the crystal cools. The now elongated crystal contains

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2002-485: Is added to the melt and defines the wafer as either bulk n-type or p-type. However, compared with single-crystal silicon's atomic density of 5×10 atoms per cm , this still gives a purity greater than 99.9999%. The wafers can also be initially provided with some interstitial oxygen concentration. Carbon and metallic contamination are kept to a minimum. Transition metals , in particular, must be kept below parts per billion concentrations for electronic applications. There

2093-494: Is called padparadscha . Significant sapphire deposits are found in Australia , Afghanistan , Cambodia , Cameroon , China ( Shandong ), Colombia , Ethiopia , India Jammu and Kashmir ( Padder , Kishtwar ), Kenya , Laos , Madagascar , Malawi , Mozambique , Myanmar ( Burma ), Nigeria , Rwanda , Sri Lanka , Tanzania , Thailand , United States ( Montana ) and Vietnam . Sapphire and rubies are often found in

2184-451: Is common practice to heat natural sapphires to improve or enhance their appearance. This is done by heating the sapphires in furnaces to temperatures between 800 and 1,800 °C (1,470 and 3,270 °F) for several hours, or even weeks at a time. Different atmospheres may be used. Upon heating, the stone becomes bluer in color, but loses some of the rutile inclusions (silk). When high temperatures (1400 °C+) are used, exsolved rutile silk

2275-428: Is commonly understood as the " color " of the gemstone. Saturation refers to the vividness or brightness of the hue, and tone is the lightness to darkness of the hue. Blue sapphire exists in various mixtures of its primary (blue) and secondary hues, various tonal levels (shades) and at various levels of saturation (vividness). Blue sapphires are evaluated based upon the purity of their blue hue. Violet and green are

2366-476: Is considerable resistance to the 450 mm transition despite the possible productivity improvement, because of concern about insufficient return on investment. There are also issues related to increased inter-die / edge-to-edge wafer variation and additional edge defects. 450mm wafers are expected to cost 4 times as much as 300mm wafers, and equipment costs are expected to rise by 20 to 50%. Higher cost semiconductor fabrication equipment for larger wafers increases

2457-556: Is derived from the Latin word sapphirus , itself from the Greek word sappheiros ( σάπφειρος ), which referred to lapis lazuli . It is typically blue, but natural "fancy" sapphires also occur in yellow, purple, orange, and green colors; "parti sapphires" show two or more colors. Red corundum stones also occur, but are called rubies rather than sapphires. Pink-colored corundum may be classified either as ruby or sapphire depending on

2548-505: Is different from silicon substrate as the substrate is sapphire, while superstrate is silicon, while epitaxal layers and doping can be anything. SOS in commercial production is typically maxed out at 150 mm wafer sizes as of 2024. GaAs wafers tend to be 150 mm at largest, in commercial production as of 2024. AlN tends to be 50 mm or 2 inch wafers in commercial production, while 100 mm or 4 inch wafers are being developed as of 2024 by wafer suppliers like Asahi Kasei. However, merely because

2639-409: Is dissolved and it becomes clear under magnification. The titanium from the rutile enters solid solution and thus creates with iron the blue color. The inclusions in natural stones are easily seen with a jeweler's loupe . Evidence of sapphire and other gemstones being subjected to heating goes back at least to Roman times. Un-heated natural stones are somewhat rare and will often be sold accompanied by

2730-557: Is heavily tilted to the red end of the spectrum, thus tipping the balance to red. Color-change sapphires colored by the Cr + Fe/Ti chromophores generally change from blue or violet-blue to violet or purple. Those colored by the V chromophore can show a more pronounced change, moving from blue-green to purple. Certain synthetic color-change sapphires have a similar color change to the natural gemstone alexandrite and they are sometimes marketed as "alexandrium" or "synthetic alexandrite". However,

2821-432: Is in contrast to natural corundum crystals, which feature angular growth lines expanding from a single point and following the planar crystal faces. Chemical dopants can be added to create artificial versions of the ruby, and all the other natural colors of sapphire, and in addition, other colors never seen in geological samples. Artificial sapphire material is identical to natural sapphire, except it can be made without

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2912-503: Is perfectly circular with no flats, and the dies have a square aspect ratio, we arrive at the Gauss Circle Problem , an unsolved open problem in mathematics.) Note that formulas estimating the gross dies per wafer ( DPW ) account only for the number of complete dies that can fit on the wafer; gross DPW calculations do not account for yield loss among those complete dies due to defects or parametric issues. Nevertheless,

3003-423: Is related to wafer count, not wafer area. Cost for processes such as lithography is proportional to wafer area, and larger wafers would not reduce the lithography contribution to die cost. Nikon planned to deliver 450-mm lithography equipment in 2015, with volume production in 2017. In November 2013 ASML paused development of 450-mm lithography equipment, citing uncertain timing of chipmaker demand. In 2012,

3094-416: Is required of any mode of enhancement that has a significant effect on the gem's value. There are several ways of treating sapphire. Heat-treatment in a reducing or oxidizing atmosphere (but without the use of any other added impurities) is commonly used to improve the color of sapphires, and this process is sometimes known as "heating only" in the gem trade. In contrast, however, heat treatment combined with

3185-709: Is thought to be the third-largest star sapphire, and is currently on display at the American Museum of Natural History in New York City . The 182-carat Star of Bombay , mined in Sri Lanka and located in the National Museum of Natural History in Washington, D.C. , is another example of a large blue star sapphire. The value of a star sapphire depends not only on the weight of the stone, but also

3276-633: The Star of India , The Star of Adam and the Star of Bombay originate from Sri Lankan mines. Madagascar is the world leader in sapphire production (as of 2007) specifically its deposits in and around the town of Ilakaka . Prior to the opening of the Ilakaka mines, Australia was the largest producer of sapphires (such as in 1987). In 1991 a new source of sapphires was discovered in Andranondambo, southern Madagascar. The exploitation started in 1993, but

3367-566: The chromium chromophore that creates the red color of ruby, combined with the iron + titanium chromophore that produces the blue color in sapphire. A rarer type, which comes from the Mogok area of Myanmar, features a vanadium chromophore, the same as is present in Verneuil synthetic color-change sapphire. Virtually all gemstones that show the "alexandrite effect" (color change or ' metamerism ') show similar absorption/transmission features in

3458-545: The insulating substrates of special-purpose solid-state electronics such as integrated circuits and GaN -based blue LEDs . Sapphire is the birthstone for September and the gem of the 45th anniversary . A sapphire jubilee occurs after 65 years. Sapphire is one of the two gem-varieties of corundum , the other being ruby (defined as corundum in a shade of red). Although blue is the best-known sapphire color, it occurs in other colors, including gray and black, and also can be colorless. A pinkish orange variety of sapphire

3549-665: The 12.00 carat Cartier sapphire ring at US$ 193,975 per carat, then with a 17.16 carat sapphire at US$ 236,404, and again in June 2015 when the per-carat auction record was set at US$ 240,205. At present, the world record price-per-carat for sapphire at auction is held by a sapphire from Kashmir in a ring, which sold in October 2015 for approximately US$ 242,000 per carat ( HK$ 52,280,000 in total, including buyer's premium, or more than US$ 6.74 million). Sapphires can be treated by several methods to enhance and improve their clarity and color. It

3640-520: The 1940s. By 1960, silicon wafers were being manufactured in the U.S. by companies such as MEMC / SunEdison . In 1965, American engineers Eric O. Ernst, Donald J. Hurd, and Gerard Seeley, while working under IBM , filed Patent US3423629A for the first high-capacity epitaxial apparatus. Silicon wafers are made by companies such as Sumco , Shin-Etsu Chemical , Hemlock Semiconductor Corporation and Siltronic . Wafers are formed of highly pure, nearly defect-free single crystalline material, with

3731-507: The 200 mm wafers, partly because a FOUP for 300 mm wafers weighs about 7.5 kilograms when loaded with 25 300 mm wafers where a SMIF weighs about 4.8 kilograms when loaded with 25 200 mm wafers, thus requiring twice the amount of physical strength from factory workers, and increasing fatigue. 300mm FOUPs have handles so that they can be still be moved by hand. 450mm FOUPs weigh 45 kilograms when loaded with 25 450 mm wafers, thus cranes are necessary to manually handle

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3822-515: The FOUPs and handles are no longer present in the FOUP. FOUPs are moved around using material handling systems from Muratec or Daifuku . These major investments were undertaken in the economic downturn following the dot-com bubble , resulting in huge resistance to upgrading to 450 mm by the original timeframe. On the ramp-up to 450 mm, the crystal ingots will be 3 times heavier (total weight

3913-524: The French chemist Auguste Verneuil announced a process for producing synthetic ruby crystals. In the flame-fusion ( Verneuil process ), fine alumina powder is added to an oxyhydrogen flame , and this is directed downward against a ceramic pedestal. Following the successful synthesis of ruby, Verneuil focused his efforts on sapphire. Synthesis of blue sapphire came in 1909, after chemical analyses of sapphire suggested to Verneuil that iron and titanium were

4004-516: The M10 standard (182 mm) are ongoing. Like other semiconductor fabrication processes, driving down costs has been the main driving factor for this attempted size increase, in spite of the differences in the manufacturing processes of different types of devices. Wafers are grown from crystal having a regular crystal structure , with silicon having a diamond cubic structure with a lattice spacing of 5.430710 Å (0.5430710 nm). When cut into wafers,

4095-698: The area of Franklin, North Carolina . The sapphire deposits of Kashmir are well known in the gem industry, although their peak production took place in a relatively short period at the end of the nineteenth and early twentieth centuries. These deposits are located in the Paddar Valley of the Jammu region of Jammu and Kashmir in India. They have a superior vivid blue hue, coupled with a mysterious and almost sleepy quality, described by some gem enthusiasts as ‘blue velvet”. Kashmir-origin contributes meaningfully to

4186-591: The biggest problem the Yogo mine faced was not competition from heated sapphires, but the fact that the Yogo stones could never produce quantities of sapphire above one carat after faceting. As a result, it has remained a niche product, with a market that largely exists in the US. Lattice ('bulk') diffusion treatments are used to add impurities to the sapphire to enhance color. This process was originally developed and patented by Linde Air division of Union Carbide and involved diffusing titanium into synthetic sapphire to even out

4277-415: The blue color. It was later applied to natural sapphire. Today, titanium diffusion often uses a synthetic colorless sapphire base. The color layer created by titanium diffusion is extremely thin (less than 0.5 mm). Thus repolishing can and does produce slight to significant loss of color. Chromium diffusion has been attempted, but was abandoned due to the slow diffusion rates of chromium in corundum. In

4368-466: The body color, visibility, and intensity of the asterism. The color of the stone has more impact on the value than the visibility of the star. Since more transparent stones tend to have better colors, the most expensive star stones are semi-transparent "glass body" stones with vivid colors. On 28 July 2021, the world's largest cluster of star sapphires, weighing 510 kg (1,120 lb), was unearthed from Ratnapura, Sri Lanka. This star sapphire cluster

4459-436: The case of silicon, can be added to the molten intrinsic material in precise amounts in order to dope the crystal, thus changing it into an extrinsic semiconductor of n-type or p-type . The boule is then sliced with a wafer saw (a type of wire saw ), machined to improve flatness, chemically etched to remove crystal damage from machining steps and finally polished to form wafers. The size of wafers for photovoltaics

4550-433: The cause of the blue color. Verneuil patented the process of producing synthetic blue sapphire in 1911. The key to the process is that the alumina powder does not melt as it falls through the flame. Instead it forms a sinter cone on the pedestal. When the tip of that cone reaches the hottest part of the flame, the tip melts. Thus the crystal growth is started from a tiny point, ensuring minimal strain. Next, more oxygen

4641-1278: The causes of color in corundum extant can be found in Chapter ;4 of Ruby & Sapphire: A Gemologist's Guide (chapter authored by John Emmett, Emily Dubinsky and Richard Hughes). Sapphires are mined from alluvial deposits or from primary underground workings. Commercial mining locations for sapphire and ruby include (but are not limited to) the following countries: Afghanistan , Australia , Myanmar / Burma , Cambodia , China , Colombia , India , Kenya , Laos , Madagascar , Malawi , Nepal , Nigeria , Pakistan , Sri Lanka , Tajikistan , Tanzania , Thailand , United States, and Vietnam . Sapphires from different geographic locations may have different appearances or chemical-impurity concentrations, and tend to contain different types of microscopic inclusions. Because of this, sapphires can be divided into three broad categories: classic metamorphic, non-classic metamorphic or magmatic, and classic magmatic. Sapphires from certain locations, or of certain categories, may be more commercially appealing than others, particularly classic metamorphic sapphires from Kashmir, Burma, or Sri Lanka that have not been subjected to heat-treatment. The Logan sapphire ,

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4732-459: The center of the star near the top of the dome. Occasionally, twelve-rayed stars are found, typically because two different sets of inclusions are found within the same stone, such as a combination of fine needles of rutile with small platelets of hematite ; the first results in a whitish star and the second results in a golden-colored star. During crystallization, the two types of inclusions become preferentially oriented in different directions within

4823-409: The color penetration is far greater than with titanium diffusion. In some cases, it may penetrate the entire stone. Beryllium-diffused orange sapphires may be difficult to detect, requiring advanced chemical analysis by gemological labs ( e.g. , Gübelin, SSEF , GIA , American Gemological Laboratories (AGL), Lotus Gemology . According to United States Federal Trade Commission guidelines, disclosure

4914-434: The cost of 450 mm fabs (semiconductor fabrication facilities or factories). Lithographer Chris Mack claimed in 2012 that the overall price per die for 450 mm wafers would be reduced by only 10–20% compared to 300 mm wafers, because over 50% of total wafer processing costs are lithography-related. Converting to larger 450 mm wafers would reduce price per die only for process operations such as etch where cost

5005-470: The crystal, thereby forming two six-rayed stars that are superimposed upon each other to form a twelve-rayed star. Misshapen stars or 12-rayed stars may also form as a result of twinning . The inclusions can alternatively produce a cat's eye effect if the girdle plane of the cabochon is oriented parallel to the crystal's c-axis rather than perpendicular to it. To get a cat's eye, the planes of exsolved inclusions must be extremely uniform and tightly packed. If

5096-690: The deliberate addition of certain specific impurities (e.g. beryllium, titanium, iron, chromium or nickel, which are absorbed into the crystal structure of the sapphire) is also commonly performed, and this process can be known as "diffusion" in the gem trade. However, despite what the terms "heating only" and "diffusion" might suggest, both of these categories of treatment actually involve diffusion processes. The most complete description of corundum treatments extant can be found in Chapter 6 of Ruby & Sapphire: A Gemologist's Guide (chapter authored by John Emmett, Richard Hughes and Troy R. Douthit). In 1902,

5187-466: The diameter of wafers that they are tooled to produce. The diameter has gradually increased to improve throughput and reduce cost with the current state-of-the-art fab using 300 mm , with a proposal to adopt 450 mm . Intel , TSMC , and Samsung were separately conducting research to the advent of 450 mm " prototype " (research) fabs , though serious hurdles remain. Wafers grown using materials other than silicon will have different thicknesses than

5278-448: The dome is oriented in between these two directions, an off-center star will be visible, offset away from the high point of the dome. At 1404.49 carats, The Star of Adam is the largest known blue star sapphire. The gem was mined in the city of Ratnapura, southern Sri Lanka. The Black Star of Queensland , the second largest star sapphire in the world, weighs 733 carats . The Star of India mined in Sri Lanka and weighing 563.4 carats

5369-418: The edge correction is negligible. The correction factor or correction term generally takes one of the forms cited by De Vries: Studies comparing these analytical formulas to brute-force computational results show that the formulas can be made more accurate, over practical ranges of die sizes and aspect ratios, by adjusting the coefficients of the corrections to values above or below unity, and by replacing

5460-500: The end of this decade). Mark LaPedus of semiengineering.com reported in mid-2014 that chipmakers had delayed adoption of 450 mm "for the foreseeable future." According to this report some observers expected 2018 to 2020, while G. Dan Hutcheson, chief executive of VLSI Research, didn't see 450mm fabs moving into production until 2020 to 2025. The step up to 300 mm required major changes, with fully automated factories using 300 mm wafers versus barely automated factories for

5551-465: The extent that it does, it's a long way out in the future. There is not a lot of necessity for Micron, at least over the next five years, to be spending a lot of money on 450mm." "There is a lot of investment that needs to go on in the equipment community to make that happen. And the value at the end of the day – so that customers would buy that equipment – I think is dubious." As of March 2014, Intel Corporation expected 450 mm deployment by 2020 (by

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5642-527: The fact that the 300mm manufacturing optimization is more cheap than costly 450mm transition may also have played a role. The timeline for 450 mm has not been fixed. In 2012, it was expected that 450mm production would start in 2017, which never realized. Mark Durcan, then CEO of Micron Technology , said in February 2014 that he expects 450 mm adoption to be delayed indefinitely or discontinued. "I am not convinced that 450mm will ever happen but, to

5733-484: The flaws that are found in natural stones. The disadvantage of the Verneuil process is that the grown crystals have high internal strains. Many methods of manufacturing sapphire today are variations of the Czochralski process , which was invented in 1916 by Polish chemist Jan Czochralski . In this process, a tiny sapphire seed crystal is dipped into a crucible made of the precious metal iridium or molybdenum , containing molten alumina, and then slowly withdrawn upward at

5824-436: The highest premium, although Burma, Sri Lanka, and Madagascar also produce large quantities of fine quality gems. The cost of natural sapphires varies depending on their color, clarity, size, cut , and overall quality. Sapphires that are completely untreated are worth far more than those that have been treated. Geographical origin also has a major impact on price. For most gems of one carat or more, an independent report from

5915-558: The increase in wafer area, while the cost of the unit fabrication step goes up more slowly than the wafer area. This was the cost basis for increasing wafer size. Conversion to 300 mm wafers from 200 mm wafers began in early 2000, and reduced the price per die for about 30–40%. Larger diameter wafers allow for more die per wafer. M1 wafer size (156.75 mm) is in the process of being phased out in China as of 2020. Various nonstandard wafer sizes have arisen, so efforts to fully adopt

6006-434: The individual microcircuits are separated by wafer dicing and packaged as an integrated circuit. In the semiconductor industry, the term wafer appeared in the 1950s to describe a thin round slice of semiconductor material, typically germanium or silicon. The round shape characteristic of these wafers comes from single-crystal ingots usually produced using the Czochralski method . Silicon wafers were first introduced in

6097-634: The intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Star_sapphire&oldid=1136782319 " Category : Disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages Sapphire#Star sapphire Sapphire is a precious gemstone , a variety of the mineral corundum , consisting of aluminium oxide ( α- Al 2 O 3 ) with trace amounts of elements such as iron , titanium , cobalt , lead , chromium , vanadium , magnesium , boron , and silicon . The name sapphire

6188-666: The largest faceted gem-quality blue sapphires in existence. Particolored sapphires (or bi-color sapphires) are those stones that exhibit two or more colors within a single stone. The desirability of particolored or bi-color sapphires is usually judged based on the zoning or location of their colors, the colors' saturation, and the contrast of their colors. Australia is the largest source of particolored sapphires; they are not commonly used in mainstream jewelry and remain relatively unknown. Particolored sapphires cannot be created synthetically and only occur naturally. Pink sapphires occur in shades from light to dark pink, and deepen in color as

6279-411: The latter term is a misnomer: synthetic color-change sapphires are, technically, not synthetic alexandrites but rather alexandrite simulants . This is because genuine alexandrite is a variety of chrysoberyl : not sapphire, but an entirely different mineral from corundum. Large rubies and sapphires of poor transparency are frequently used with suspect appraisals that vastly overstate their value. This

6370-434: The linear die dimension S {\displaystyle {\sqrt {S}}} with ( H + W ) / 2 {\displaystyle (H+W)/2} (average side length) in the case of dies with large aspect ratio: While silicon is the prevalent material for wafers used in the electronics industry , other compound III-V or II-VI materials have also been employed. Gallium arsenide (GaAs),

6461-679: The locale. Commonly, natural sapphires are cut and polished into gemstones and worn in jewelry . They also may be created synthetically in laboratories for industrial or decorative purposes in large crystal boules . Because of the remarkable hardness of sapphires – 9 on the Mohs scale (the third-hardest mineral, after diamond at 10 and moissanite at 9.5) – sapphires are also used in some non-ornamental applications, such as infrared optical components, high-durability windows , wristwatch crystals and movement bearings, and very thin electronic wafers , which are used as

6552-547: The mid of 2014 CNSE has announced that it will reveal first fully patterned 450mm wafers at SEMICON West. In early 2017, the G450C began to dismantle its activities over 450mm wafer research due to undisclosed reasons. Various sources have speculated that demise of the group came after charges of bid rigging made against Alain E. Kaloyeros , who at the time was a chief executive at the SUNY Poly. The industry realization of

6643-406: The most common secondary hues found in blue sapphires. The highest prices are paid for gems that are pure blue and of vivid saturation. Gems that are of lower saturation, or are too dark or too light in tone are of less value. However, color preferences are a personal taste. The 423-carat (84.6 g) Logan sapphire in the National Museum of Natural History , in Washington, D.C. , is one of

6734-531: The most effective methods is the RCA clean . When used for solar cells , the wafers are textured to create a rough surface to increase surface area and so their efficiency. The generated PSG ( phosphosilicate glass ) is removed from the edge of the wafer in the etching . Silicon wafers are available in a variety of diameters from 25.4 mm (1 inch) to 300 mm (11.8 inches). Semiconductor fabrication plants , colloquially known as fabs , are defined by

6825-443: The number of gross DPW can be estimated starting with the first-order approximation or floor function of wafer-to-die area ratio, where This formula simply states that the number of dies which can fit on the wafer cannot exceed the area of the wafer divided by the area of each individual die. It will always overestimate the true best-case gross DPW, since it includes the area of partially patterned dies which do not fully lie on

6916-648: The quantity of chromium increases. The deeper the pink color, the higher their monetary value . In the United States, a minimum color saturation must be met to be called a ruby , otherwise the stone is referred to as a pink sapphire . Padparadscha is a delicate, light to medium toned, pink-orange to orange-pink hued corundum , originally found in Sri Lanka , but also found in deposits in Vietnam and parts of East Africa . Padparadscha sapphires are rare;

7007-522: The rarest of all is the totally natural variety, with no sign of artificial treatment. The name is derived from the Sanskrit padma ranga (padma = lotus; ranga = color), a color akin to the lotus flower ( Nelumbo nucifera ). Among the fancy (non-blue) sapphires, natural padparadscha fetch the highest prices. Since 2001, more sapphires of this color have appeared on the market as a result of artificial lattice diffusion of beryllium. A star sapphire

7098-463: The same geographical settings, but they generally have different geological formations. For example, both ruby and sapphire are found in Myanmar's Mogok Stone Tract, but the rubies form in marble, while the sapphire forms in granitic pegmatites or corundum syenites. Every sapphire mine produces a wide range of quality, and origin is not a guarantee of quality. For sapphire, Jammu and Kashmir receives

7189-545: The surface is aligned in one of several relative directions known as crystal orientations. Orientation is defined by the Miller index with (100) or (111) faces being the most common for silicon. Orientation is important since many of a single crystal's structural and electronic properties are highly anisotropic . Ion implantation depths depend on the wafer's crystal orientation, since each direction offers distinct paths for transport. Wafer cleavage typically occurs only in

7280-412: The transfer of an electron from one transition-metal ion to another via the conduction or valence band . The iron can take the form Fe or Fe , while titanium generally takes the form Ti . If Fe and Ti ions are substituted for Al , localized areas of charge imbalance are created. An electron transfer from Fe and Ti can cause a change in the valence state of both. Because of the valence change, there

7371-506: The value of a sapphire, and most corundum of Kashmir origin can be readily identified by its characteristic silky appearance and exceptional hue. The unique blue appears lustrous under any kind of light, unlike non-Kashmir sapphires which may appear purplish or grayish in comparison. Sotheby's has been in the forefront overseeing record-breaking sales of Kashmir sapphires worldwide. In October 2014, Sotheby's Hong Kong achieved consecutive per-carat price records for Kashmir sapphires – first with

7462-445: The visible spectrum. This is an absorption band in the yellow (~590 nm), along with valleys of transmission in the blue-green and red. Thus the color one sees depends on the spectral composition of the light source. Daylight is relatively balanced in its spectral power distribution (SPD) and since the human eye is most sensitive to green light, the balance is tipped to the green side. However incandescent light (including candle light)

7553-562: The wafer increases with its thickness and the square of its diameter. Date of introduction does not indicate that factories will convert their equipment immediately, in fact, many factories do not bother upgrading. Instead, companies tend to expand and build whole new lines with newer technologies, leaving a large spectrum of technologies in use at the same time. GaN substrate wafers typically have had their own independent timelines, parallel but far lagging silicon substrate, but ahead of other substrates. The world's first 300 mm wafer made of GaN

7644-460: The wafer surface (see figure). These partially patterned dies don't represent complete ICs , so they usually cannot be sold as functional parts. Refinements of this simple formula typically add an edge correction, to account for partial dies on the edge, which in general will be more significant when the area of the die is large compared to the total area of the wafer. In the other limiting case (infinitesimally small dies or infinitely large wafers),

7735-534: The world's production of synthetic sapphire was 250 tons (1.25 × 10 carats), mostly by the United States and Russia. The availability of cheap synthetic sapphire unlocked many industrial uses for this unique material. Wafer (electronics) The wafer serves as the substrate for microelectronic devices built in and upon the wafer. It undergoes many microfabrication processes, such as doping , ion implantation , etching , thin-film deposition of various materials, and photolithographic patterning. Finally,

7826-416: The year 2000, beryllium diffused "padparadscha" colored sapphires entered the market. Typically beryllium is diffused into a sapphire under very high heat, just below the melting point of the sapphire. Initially ( c.  2000 ) orange sapphires were created, although now the process has been advanced and many colors of sapphire are often treated with beryllium. Due to the small size of the beryllium ion,

7917-542: Was announced in Sept 2024 by Infineon, suggesting in the coming future they could put into use the first factory with 300 mm GaN commercial output. Meanwhile world's first Silicon Carbide (SiC) 200 mm wafers were announced in July 2021 by ST Microelectronics. It is not known if SiC 200 mm has entered volume production as of 2024, as typically the largest fabs for SiC in commercial production remain at 150 mm. Silicon on sapphire

8008-490: Was named " Serendipity Sapphire ". A rare variety of natural sapphire, known as color-change sapphire, exhibits different colors in different light. Color change sapphires are blue in outdoor light and purple under incandescent indoor light, or green to gray-green in daylight and pink to reddish-violet in incandescent light. Color-change sapphires come from a variety of locations, including Madagascar , Myanmar , Sri Lanka and Tanzania . Two types exist. The first features

8099-550: Was not commonly disclosed; by the late 1980s, heat treatment became a major issue. At that time, much of all the world's sapphires were being heated to enhance their natural color. Intergem's marketing of guaranteed untreated Yogos set them against many in the gem industry. This issue appeared as a front-page story in The Wall Street Journal on 29 August 1984 in an article by Bill Richards, Carats and Schticks: Sapphire Marketer Upsets The Gem Industry . However,

8190-613: Was practically abandoned just a few years later because of the difficulties in recovering sapphires in their bedrock. In North America , sapphires have been mined mostly from deposits in Montana : facies along the Missouri River near Helena, Montana , Dry Cottonwood Creek near Deer Lodge, Montana , and Rock Creek near Philipsburg, Montana . Fine blue Yogo sapphires are found at Yogo Gulch west of Lewistown, Montana . A few gem-grade sapphires and rubies have also been found in

8281-672: Was the case of the "Life and Pride of America Star Sapphire". Circa 1985, Roy Whetstine claimed to have bought the 1905-ct stone for $ 10 at the Tucson gem show, but a reporter discovered that L.A. Ward of Fallbrook, California, who appraised it at the price of $ 1200/ct, had appraised another stone of the exact same weight several years before Whetstine claimed to have found it. Bangkok-based Lotus Gemology maintains an updated listing of world auction records of ruby, sapphire, and spinel . As of November 2019, no sapphire has ever sold at auction for more than $ 17,295,796. Rubies are corundum with

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