Growth Characteristics of Alpha-Silicon Carbide

The equilibrium partial pressures of various vapor species in the system silicon‐carbon‐hydrogen were computed for conditions under which epitaxial normalSiC deposition has been achieved. It was found that in the temperature range 1300°–1700°C the tendency to form solid silicon carbide decreases with increasing temperature and with increasing silicon to carbon atom ratio. The limiting conditions under which single crystalline deposits of α‐normalSiC could be experimentally obtained were those within which normalSiC was computed to be the only thermodynamically stable solid phase. At 1650° single‐phase silicon carbide condenses at normalSi/C ratios ranging from 0.2 to 0.89. The computed results were in good agreement with experiments.

supporting

confidence: 90%

“…The experimental conditions for single crystalline deposition of epitaxial a-SiC were examined in an earlier study (1). At present, the results of theoretical computations of equilibrium vapor pressures in the system silicon-carbon-hydrogen are reported and correlated with experimental findings.…”

mentioning

confidence: 96%

Growth Characteristics of Alpha-Silicon Carbide

Harris¹,

Gatos²,

Witt³

1971

“…The SEM pictures of the o.f the deposits slightly decreases with the increase in the d e p o s i t i o n temperature. These results i m p l y that the shape of the curves arises due to the existence of two different kinetic regimes; i.e., at lower t e m p e r a t u r e s the growth rate curves characterize the activation energy of the rate-limiting reaction at the substrate surface, the subsequent decrease in growth rate at the higher temperature curves, after the growth rate reaches its maximum, can be explained by reactions in the diffusion layer leading to enhanced etching effects on the substrate surface (9)(10)(11). The effect of MTS flux on the deposition rate is E x a m i n a t i o n of the faceted crystals shows that they contain m a n y clear twin configurations and r e e n t r a n t corners.…”

Section: Resultsmentioning

confidence: 99%

“…In addition to the most commonly used SiO2 mask, other dielectrics such as SiNx, A1N, and shadow masks have been used for patterning the growth (7)(8)(9). Although GaAs native oxide masks have been utilized with MBE (10,11), applying native oxide masks to the higher temperature selective OMCVD process has not been previously studied.…”

Section: Introductionmentioning

confidence: 99%

Growth Characteristics of CVD Beta‐Silicon Carbide

Cheng

Shyy

Kuo

et al. 1987

The films of B-SiC were prepared from the methyltrichlorosilane (MTS) by low pressure chemical vapor deposition onto the graphite substrates. The results revealed that the growth rate of ~-SiC increased with the MTS flux; besides, the growth rate increased to a maximum and then decreased with increasing deposition temperature. The preferred orientation of the films was examined by x-ray diffraction, and was found to exhibit a (220) texture in the films of high growth rate and/or long deposition time. The structural morphology was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Observed features indicated the twin plane reentrant edge (TPRE) mechanism as responsible for the B-SiC growth. The growth features of particulate crystals (e.g., dendrites, whiskers, needles) were identified, and also could be interpreted in terms of the TPRE mechanism.Silicon carbide (SIC) is a refractory compound with much promise for certain electronic, optical, and structural applications. Its wide energy bandgap and high saturated drift velocityshould make it a useful high temperature semiconductor. By virtue of its intrinsic oxidation, corrosion and creep resistance at high temperature, as well as its high thermal conductivity, extreme hardness, low neutron absorption cross section, and excellent resistance to chemical attack and thermal shock, SiC is of considerable interest in several fields of science and technology connected with the production or transformation of energy. Additionally, SiC is an excellent infrared transmitting material because it has a cutoff in the IR beyond 5.5 ~m (1-3). The cubic form of B-SiC has a forbidden energy gap of 2.3 eV. This poly-type is also relatively easy to grow at relatively low temperatures via solution or vapor phase deposition routes.B-SiC crystals have been grown by many investigators using chemical vapor deposition (CVD) (4-6) 9 In these papers, methyltrichlorosilane (MTS) was most frequently used, because it has a 1:1 molar ratio of silicon to carbon which results in the deposition of a dense stoichiometric SiC deposit. Essentially, all the studies were concerned with the growth or characterization of SiC. Additionally, the microstructure and the growth mechanism of deposits have also been discussed by several investigators (6-8). The growth mechanism determines the nature of defects and the form of the particulate crystals (e.g., dendrite, whisker, needle), both of which are of prime importance in all applications. The particulate crystal growth, especially in the CVD process, is even more evident as the growth time increases. So, a better understanding of the growth mechanism may aid in improving the quality of crystal and obtaining a larger size crystal.In this paper, crystals of ~-SiC were chemically vapor deposited on graphite substrates by thermal decomposition of CH3SiC13 carried in a flowing hydrogen. An important objective of this study was to characterize the growth mechanism of the R-SiC by investigating the microstructure of the...

“…As with other thin film materials such as polysilicon, silicon nitride, and tungsten, silicon carbide has been made mostly by chemical vapor deposition. It has been known that two kinds of singlecrystal silicon carbide (hexagonal [alpha] or cubic [beta] structure) were formed around 1600~ and that films deposited at 1000~ or below were in polycrystalline or amorphous state (1)(2)(3)(4).…”

mentioning

confidence: 99%

Computer Simulation Study on Atmospheric Pressure CVD Process for Amorphous Silicon Carbide

Koh

Woo

1990

Mathematical modeling and simulation study of horizontal chemical vapor deposition reactor in the APCVD process for SiC were carried out for the prediction of film growth rate and uniformity and for the investigation of the effects of reactant flow and other operating conditions. In order to solve two-dimensional momentum, energy, and material balance equations, finite volume numerical analysis was used. Experimental data were obtained in an atmospheric reactor for the reaction of CH4 and Sill4 in H2 to produce amorphous SiC film on silicon wafer at 650~176 Kinetic rate expression obtained from the regression of the experimental deposition rate data was used for the simulation of large scale production of thin films. At a high reaction rate, low flow rate or large temperature gradients increase film nonuniformity and at a low total pressure uniform film growth was assured. Our computation simulation model also considers the changes in the transport rate coefficients such as viscosity, thermal conductivity, and diffusivity with the changes in temperature, pressure, and the composition of reactant gases inside reactor.