What are Silicon Wafer Crystalline Defects?

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Crystalline Defects In Silicon Wafer

The task is to make a single crystal silicon wafer with only one crystal with a defect free of a region on it, and this is the subject of the present invention and has the potential to be used in high-performance electronics and other electronic devices such as computers and televisions. This should facilitate the formation of fault-free regions and the securing of the electronic circuits on silicon wafers. [Sources: 5, 8]

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Semiconductor Crystalline Defects

A semiconductor wafer must be free of significant defects in order to secure the various electronic circuits that form on it. One day, when ingots grow on the space station, silicon will be forgotten, and one day the big silicon manufacturers will make incredible silicon discs again, but until that point, no one has made a perfect one. Silicon wafers have many defects, most of which can be found at the silicon manufacturer. While certain types of defects are crucial in semiconductor manufacturing, the presence of most crystalline defects is undesirable, especially in high-performance electronics and other electronic devices, such as the electronic components of computers and televisions. Silicon waves have many hidden faults, most of them have been found on silicon manufacturing plants and even in silicon chips, they have had many faults and in most cases they are only found in a small number of silicon chip manufacturers. [Sources: 3, 4, 11]

B Bare CZ silicon wafers with a diameter of 300 mm are treated with gaseous acid in a reduced atmosphere to produce crystal defects. In order to detect defects in light scattering, the crystal defect is magnified to a size that can be detected as light scattering defect. For analysis, a 300mm silicon wafer is carefully etched from the gaseous acid at a reducing atmosphere and temperature and decorated with the crystals of the defect, then treated in the same way in a different environment with a reduced atmosphere and grown over several days without crystals or defects. [Sources: 1]

In addition, such grown defects are thermally stable and remain in the active region of the wafer surface where they deteriorate as described above. The COP assessment is performed on silicon wafers that have an extremely low amount of Grown Defects. [Sources: 6, 12]

Generally, the accumulation of voids and cavities in the silicon crystal caused by the crystal drawing process dissolves and resembles the easily and directly observable carbon-graphite receptors, doping and others. Defects have the advantage that they can be caused not only by a single defect, but also by several defects. The manipulation of the v - g to eliminate OSF rings does not necessarily lead to two grown defects, including infrared scattering and dislocation clusters, which can remain in a crystal. [Sources: 0, 2, 6]

A defect where a silicon atom is missing at one point is called a void defect, and when this atom is found, it becomes an interstitial silicon point defect. A vacancy of this kind or a "point defect" is caused by the accumulation of silicon atoms in two places in the silicon crystal, one at the point of the crystal and the other at another place. This is called a self- or "interstitial defect" because there are two different types of defects in a single silicon wafer. [Sources: 4, 8]

When an atom is located at a non-lattice-like location in the crystal, it is called an interstitial defect and vice versa. [Sources: 4]

The advantages are price; while a two-inch silicon wafer costs only a few dollars, values for similar silicon carbide wafers run into the thousands. Disadvantages, including price, mean that a so-called "growing defect" - the ability of silicon in a single crystal to draw at such high tensile rates and deteriorate at high temperatures due to interstitial silicon agglomerates - exists. Assuming there is a displacement or residue large enough for defects in the interstitial silicon to be dominant in this region, and that a defect exists in an interstitial - silicon agglomerate in this region - then the silicon wafer is actually a wafer that does not include such a region. A comparison of the bonded silicon on a silicon wafer with an unbonded, unbonded, single crystalline silicon shows, for example, that both have so-called "grown defects." [Sources: 6, 7, 8, 10]

Based on these findings, we investigated whether the crystal defects that occur on the wafer surface are closely linked to the surface morphology and whether they influence the flow and growth steps. In the defective areas there are warping and stacking errors; local losses occur with structural regularity; stacked errors occur easily; and etching features are found in both the etched defects and the interstitial silicon agglomerates. Accordingly, it is abbreviated to remove the heavy metals such as lead, arsenic, mercury, cadmium, cobalt, nickel, copper, zinc, iron, lead and other metals. [Sources: 0, 9, 13]

There are external point defects that are included in the point defect, which includes foreign atoms such as lead, arsenic, mercury, cadmium, cobalt, nickel, copper, zinc, iron, lead and other metals. [Sources: 4]

 

 

Sources:

[0]: https://patents.google.com/patent/US5902135A/en

[1]: https://www.azonano.com/article.aspx?ArticleID=4306

[2]: https://www.scirp.org/journal/paperinformation.aspx?paperid=79161

[3]: http://www.google.com/patents/US20020046694

[4]: https://www.eesemi.com/crystaldefects.htm

[5]: https://www.google.com/patents/DE10236023A1?cl=en

[6]: http://www.google.com.na/patents/USRE39173

[7]: https://www.eurekalert.org/pub_releases/2019-08/thni-trt082919.php

[8]: https://www.google.ch/patents/US7632349

[9]: http://www.seas.ucla.edu/~goorsky/pres/AbsICCG01_1pg.htm

[10]: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4927739/

[11]: https://www.universitywafer.com/silicon-wafer-defects.html

[12]: https://www.google.com.pg/patents/US8173449

[13]: https://www.hitachi-hightech.com/global/sinews/si_report/0610/

 

Silicon Wafer Crystalline Defects

Crystalline defects are irregularities of normal crystalline patterns in solids. They occur most frequently in organic solvents because of their high rate of vaporization. They are very common in polycrystalline compounds, where crystal lattices exhibit a repeating periodic crystalline structure, and are therefore common in materials such as glass, ceramic, porcelain, and quartz. Their appearance is sometimes called "cavity streaks" or "icing". Since defects often cause an excess of crystalline surface area that contacts the substrate, the defects can be quite pronounced and costly to remedy. They are therefore important to mechanical testing.

solving silicon wafer surface defects

Crystalline vacancies are most common in quartz. Although impurities cannot be seen, visual inspection shows areas of higher stress concentration, due to crystalline movement. Most impure vacancies have no influence on the mechanical properties of a material, but when defects cause a granule dislocation within a quartz piece, the stress concentration in the interior can be high enough to dislodge a particle. This process can be used in many industries to increase fatigue life, reduce tensile strength, and create a smooth surface. Other uses include bumpers in sealants, slots and ramps in electronic devices, and mechanical fasteners in brazing.

Most defects found in crystalline materials are caused by a minor contact barrier between the substrate and crystalline interface. This is referred to as a "dipole moment". A much larger area of free liquid is found between the two interfaces than is the case with regular crystalline structures, because the free liquids usually do not contain a significant amount of crystalline structure. The contact is usually too weak for a significant amount of energy to transfer from the substrate to the defect. The crystals usually respond by growing into the gap, pushing the substrate out. The process of crystallization causes the flaws, or crystallites, that are found as defects in the material.

Crystalline defects, when present, must first be allowed to grow and then be fixed. It may be very difficult to identify mechanical properties of a crystalline sample that have been changed due to the reaction of the substrate with the impurity. Crystalline growth in itself is random, so it can sometimes be hard to judge the mechanical properties that are affected by the process. Most defects will return to their original mechanical properties after the substrate has passed through the impurity.

Some common crystalline defects include buckling, flaking, and lamination. Buckling occurs when the stress applied to the sample causes a microscopic crack in the material, allowing water to seep through. If the crack is located near the surface of the crystal, the surface tension of the liquid may cause the crystal to bulge, forming a visible defect.

 

Flaking is the most common of the defects, and occurs when there is a low or high salt content in the sample. Because of this, the sample becomes saturated with salt before the impurities are absorbed. Once the sample is cooled below the equilibrium level, the excess salt drops from the sample onto the surface, forming a lamination. This is a very common defect and can be detected with a refractory test.

Crystalline or parasitic texturing is often mistaken for porosity, as it is both physically and chemically diverse from porosities. However, texturing occurs when the crystal is exposed to a high salt concentration, causing the material to change from a solid to a semi-solid. When the process is slow enough, it can form a layer on the surface of the crystal that is identical to the rest of the material. This makes it appear as though the surface has no pores, but when high enough, it allows small leaks to develop.

Crystalline defects in materials range widely in both depth and width. Some examples of these defects include amorphous, cycloidal, dipteranoid and mixed. The amorphous variety displays irregular crystals which tend to look like a honey comb, while cycloidal displays irregular stripes of waxy substances. These irregular forms are produced by random crystallization.