Silicon epitaxy

Silicon Epitaxy. A critical step ia IC fabricatioa is the epitaxial depositioa of sdicoa oa an iategrated circuit. Epitaxy is defined as a process whereby a thin crystalline film is grown on a crystalline substrate. Silicon epitaxy is used ia bipolar ICs to create a high resistivity layer oa a low resistivity substrate. Most epitaxial depositioas are doae either by chemical vapor depositioa (CVD) or by molecular beam epitaxy (MBE) (see Thin films). CVD is the mainstream process. 

A more elaborate example of induct on heating is shown in Fig. 5.8, which showsareactordesignedforthedeposition of silicon epitaxy in semiconductor devices (see Ch. 13).Thepowerissuppliedby a solid-state high-frequency (20 KHz) generator. A radiation reflector, shown in Detail A, increases the efficiency and uniformity of deposition. Pressure varies from 100 mbar to 1 atm. 

Figure 5.8. Schematic of cold-wall production reactorfor silicon epitaxy.

Silicon Epitaxy. Silicon epitaxial films have superior properties. The applications are, however, limited by the high temperature of deposition, which is generally above 1000°C. These reactions use chlorinated compounds of silicon (tetrachloride, trichlorosilane, or dichlorosilane) as precursors as follows ... 

Reif, R., Low Temperature Silicon Epitaxy by Plasma Enhanced CVD, Proc. 5th European Conf. on CVD, (J. Carlsson and J. Lindstrom, eds.), pp. 13-19, Univ. ofUppsala, Sweden (1985)... 

CVD reactors operate at sufficiently high pressures and large characteristic dimensions (e.g., wafer spacing) such that Kn (Knudsen number) << 1, and a continuum description is appropriate. Exceptions are the recent vacuum CVD processes for Si (22, 23) and compound semiconductors (156, 157, 169) that work in the transition to the free molecular flow regime, that is, Kn > 1. Figure 7 gives an example of SiH4 trajectories in nearly free molecular flow (Kn 10) in a very low pressure CVD system for silicon epitaxy that is similar to that described by Meyerson et al. (22, 23 Meyerson and Jensen, manuscript in preparation). Wall collisions dominate, and be-... 

Other systems can be treated in a similar manner such as the Ti-B-CI-H system,10 and of course the Si-H-CI system has been exhaustively studied because of the commercial importance of silicon epitaxial films used for integrated circuit fabrication.11... 

Atherton, R.W., Fundamentals of silicon epitaxy. Semiconductor Inter-... 

The structures were grown in an ultra high vacuum (UHV) chamber VARIAN with a base pressure of 2-10 °Torr equipped with differential reflectance spectroscopy (DRS) [3] for a study of optical properties of the samples. Samples were cut from n-type 0.3 D cm Si(l 11) substrates. The silicon was cleaned by flashes at 1250 °C (7 times). Surface purity was controlled by AES. RDE was carried out at 500 °C, 550 °C, and 600 °C. The Cr deposition rate was about 0.04 nm/min controlled by a quartz sensor. An additional annealing during 2 min at 700 °C was done for all samples before the growth of silicon epitaxial cap layer. 

V. D. Archer, Methods for defect evaluation of thin <100> orientated silicon epitaxial layers using a wet chemical etch, J. Electrochem. Soc. 129, 2074, 1982... 

Boron is another possible p-type dopant. The incorporation of boron into silicon epitaxial layers grown from a tin melt has been studied by Baliga [15] and McCann [16]. Boron is provided via the silicon source wafer and its incorporation is a function of both time and temperature. Its segregation coefficient from liquid tin into solid silicon is temperature dependent and increases with temperature. Therefore, the content of boron into the layer will be maximum at the interface and minimum at the final surface. This doping gradient can be used to create a drift field in the base layer of the... 

Silicon epitaxy involves different types of chemical reactions according to the considered precursors. The gas precursors are SiED (silane), or chlorinated compounds like SiC L (silicon tetrachloride), Si 11C I a, (trichlorosilane), or SiE CD (dichlorosilane). The choice of precursor inevitably directs the epitaxy technique and the working temperature [8] ... 

The modern microelectronics and semiconductor industries have imposed severe demands on the quality of films produced by the silicon epitaxy process and the epitaxial film deposition techniques need to fulfill several general... 

Violette, K.E. O Neil, P.A. Ozturk, M.C. Christensen, K. Maher, D.M. Low temperature selective silicon epitaxy by ultra high vacuum rapid thermal chemical vapor deposition using Si2He, H2 and CI2. Appl. Phys. Lett. 1996, 68 ), 66-68. 

The deposition rate may be raised by using higher deposition temperatures. A standard process in the IC world is silicon epitaxy, which deposits tens of micro-... 

Reber S, Pocza D, Keller M, Arnold M, Schillinger N, Krogull D (2012) Advances in equipment and process development for high-throughput continuous silicon epitaxy. In 27th European photovoltaic solar energy conference and exhibition, Frankfurt. WIP-Renewable Energy, Munich, pp 2466-2470... 

Cohen U, Huggins RA (1976) Silicon epitaxial growth by electrodeposition from molten fluorides. J Electrochem Soc 123 381-383... 

Amorphous, microcrystalline, polycrystalline, and single-crystalline silicon are important building blocks in the construction of miniature silicon architectures by microlithography. Each silicon crystallinity has a slightly different characteristic Raman shift associated with the silicon first-phonon band. LCTF Raman chemical imaging can be applied to measure the distribution of silicon crystallinities within an integrated-circuit test pattern. The test pattern contains single-crystal silicon with a thin oxide layer and polycrystalline silicon epitaxially deposited on the monocrystalline silicon substrate. 

M Broiukowski, Y Wang, RJ Hamers. Antiphase boundaries and nucleation centers in low-temperature silicon epitaxial growth. Phys Rev B 48 12361, 1993. 

Low temperature silicon surface cleaning is carried out by fluoric acid (HF) etching, washing, cleaning with deionized water, N-gas blowing, UV-ozone treatment. This is a treatment preceding the process of silicon epitaxy [158-160],... 

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