skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Chemical Vapor Deposition of Silicon Carbide Epitaxial Films and their Characterization

Abstract

A chemical vapor deposition (CVD) system was designed and fabricated in our laboratory and SiC homo-epitaxial layers were grown in the CVD process using silicon tetrachloride and propane precursors with hydrogen as a carrier gas. The temperature field was generated using numerical modeling. Gas flow rates, temperature field, and the gradients are found to influence the growth rates of the epitaxial layers. Growth rates were found to increase as the temperature increased at high carrier gas flow rate, while at lower carrier gas flow rate, growth rates were observed to decrease as the temperature increased. Based on the equilibrium model, 'thermodynamically controlled growth' accounts for the growth rate reduction. The grown epitaxial layers were characterized using various techniques. Reduction in the threading screw dislocation (SD) density in the epilayers was observed. Suitable models were developed for explaining the reduction in the SD density as well as the conversion of basal plane dislocations (BPDs) into threading edge dislocations (TEDs).

Authors:
; ; ; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
930533
Report Number(s):
BNL-80574-2008-JA
Journal ID: ISSN 0361-5235; JECMA5; TRN: US200904%%773
DOE Contract Number:
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Electronic Materials; Journal Volume: 35; Journal Issue: 4
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 08 HYDROGEN; CHEMICAL VAPOR DEPOSITION; DEFECTS; DISLOCATIONS; EDGE DISLOCATIONS; GAS FLOW; HYDROGEN; PROPANE; SCREW DISLOCATIONS; SILICON; SILICON CARBIDES; SIMULATION; national synchrotron light source

Citation Formats

Dhanaraj,G., Chen, Y., Dudley, M., Cai, D., and Zhang, H. Chemical Vapor Deposition of Silicon Carbide Epitaxial Films and their Characterization. United States: N. p., 2007. Web. doi:10.1007/s11664-006-0084-2.
Dhanaraj,G., Chen, Y., Dudley, M., Cai, D., & Zhang, H. Chemical Vapor Deposition of Silicon Carbide Epitaxial Films and their Characterization. United States. doi:10.1007/s11664-006-0084-2.
Dhanaraj,G., Chen, Y., Dudley, M., Cai, D., and Zhang, H. Mon . "Chemical Vapor Deposition of Silicon Carbide Epitaxial Films and their Characterization". United States. doi:10.1007/s11664-006-0084-2.
@article{osti_930533,
title = {Chemical Vapor Deposition of Silicon Carbide Epitaxial Films and their Characterization},
author = {Dhanaraj,G. and Chen, Y. and Dudley, M. and Cai, D. and Zhang, H.},
abstractNote = {A chemical vapor deposition (CVD) system was designed and fabricated in our laboratory and SiC homo-epitaxial layers were grown in the CVD process using silicon tetrachloride and propane precursors with hydrogen as a carrier gas. The temperature field was generated using numerical modeling. Gas flow rates, temperature field, and the gradients are found to influence the growth rates of the epitaxial layers. Growth rates were found to increase as the temperature increased at high carrier gas flow rate, while at lower carrier gas flow rate, growth rates were observed to decrease as the temperature increased. Based on the equilibrium model, 'thermodynamically controlled growth' accounts for the growth rate reduction. The grown epitaxial layers were characterized using various techniques. Reduction in the threading screw dislocation (SD) density in the epilayers was observed. Suitable models were developed for explaining the reduction in the SD density as well as the conversion of basal plane dislocations (BPDs) into threading edge dislocations (TEDs).},
doi = {10.1007/s11664-006-0084-2},
journal = {Journal of Electronic Materials},
number = 4,
volume = 35,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
  • In this work, we explore the use of the chemical vapor composites (CVC) process to increase the rates of silicon carbide (SiC) growth on graphite substrates. Large SiC seed particles are used that deposit by gravity-driven sedimentation. The results show that addition of large ([ital d][sub [ital p]]=28 [mu]m) SiC seed particles to a gas phase containing hydrogen and methyltrichlorosilane increases the deposition rate of SiC by amounts substantially higher than that expected from the addition of the particle volume alone. Insight into the mechanism of this deposition rate enhancement is obtained through analysis of SEM photographs of deposits. Growthmore » rates and deposit structures are consistent with the trends predicted by the previously developed random-sphere model of simultaneous particle-vapor deposition (RASSPVDN), which is used here to interpret the data.« less
  • Spectroscopic ellipsometry was used to monitor excimer laser annealed thin ({approximately}100nm) amorphous silicon (a-Si) films grown on quartz substrates by low pressure chemical vapor deposition (LPCVD). The peak position of the imaginary part of the complex dielectric function {epsilon}{sub 2} was used to determine the degree of crystallization of the a-Si. The amplitude of {epsilon}{sub 2} at the Si E{sub 1} transition energy is found to be a good indicator of the polycrystalline silicon (poly-Si) grain size after laser annealing with good correlation between {ital ex situ} ellipsometric data and poly-Si grain sizes being observed. Spectroscopic ellipsometry provides a contactless,more » nondestructive, and simple technique for monitoring laser annealing both {ital in situ} during the annealing process or {ital ex situ} after annealing. {copyright} {ital 1997 American Institute of Physics.}« less
  • Thin silicon oxynitride (Si-N-O) films have been deposited using low pressure rapid thermal chemical vapor deposition (RTCVD), with silane (SiH[sub 4]), nitrous oxide (N[sub 2]O), and ammonia (NH[sub 3]) as the reactive gases. Structural and kinetic studies indicate that an increase in the NH[sub 3]/N[sub 2]O flow rate ratio leads to an increase N/O atomic ratio and a decreased Si-N-O deposition rate for constant SiH[sub 4] and N[sub 2]O flow rates. Experimental results show that RTCVD Si-N-O films with high throughput at low thermal budget, uniform composition, and atomically flat interface can be achieved using a SiH[sub 4]/NH[sub 3]/N[sub 2]Omore » gas mixture. Electrical characterization of poly Si/Si-N-O/Si capacitors demonstrates that for NH[sub 3]/N[sub 2]O flow rate ratios ranging from 20 to 100%, the mid-gap interface trap densities of the deposited Si-N-O films are [<=]2 [times] 10[sup 10] eV[sup [minus]1] cm[sup [minus]2] and Fowler-Nordheim electron-tunneling rather than Frenkel-Poole thermal-emission is the dominant conduction mechanism in the thin RTCVD Si-N-O films.« less
  • Silicon nitride films were synthesized at 170 deg. C by using inductively coupled plasma chemical vapor deposition under three microwave power conditions of 500, 800, and 1000 W. The chemical, physical and electrical properties of the deposited silicon nitride films were characterized by Fourier transform infrared, wet etching, atomic force microscopy, ellipsometry, J-V, and C-V measurements of metal-insulator-semiconductor. The microwave power for film deposition is found to play an important role at the films' properties. A high microwave power reduces the retention of hydrogen in a form of Si-H and N-H atomic bonds. The microwave power significantly affects the densitymore » of pin holes; the 800 W film has the lowest density of pin holes. In general, the low-temperature silicon nitride films possess better surface roughness than the conventional silicon nitride films produced at higher temperatures. The low-temperature silicon nitride films exhibit an abrupt breakdown, a characteristic of avalanche breakdown. The variation in breakdown strength is correlated with the change in pin-hole density, and the 800 W silicon nitride film possesses the highest breakdown strength. The microwave power has limited influences on leakage current and resistivity of the films. All the low-temperature silicon nitride films are characterized by high-density fixed charges and interface charge traps, of which both densities vary slightly with the microwave power for film deposition.« less
  • The morphologies of polycrystalline SiC layers and [beta]-SiC epilayers deposited onto TiC[sub x] by pyrolysis of SiH[sub 4] and C[sub 2]H[sub 4] in diluted atmospheres of Ar, He, H[sub 2], Ar + He, Ar + H[sub 2], and He + H[sub 2] were studied. The fraction of the TiC[sub x] surface covered by SiC was dependent on the diluent atmosphere and the TiC[sub x] temperature (T[sub s]). The morphology and growth rate were dependent on T[sub s], at a fixed C:Si ratio. Epilayer morphologies, similar to those reported for [beta]-SiC on Si were obtained in Ar + H[sub 2], andmore » He + H[sub 2] atmospheres, without thermal ramping, and in H[sub 2] with thermal ramping; where, the optimum C:Si ratio was a function of T[sub s]. Ratios of C:Si from 0.16 to 7.0 yielded [beta]-SiC epitaxial growth in Ar and He diluent atmospheres. The occurrence of homogeneous nucleation was strongly influence by diluted to reactant ratios and T[sub s].« less