Epitaxial Growth of Silicon Carbide on On-axis Silicon Carbide Substrates Using Methyltrichlorosilane Chemical Vapor Deposition

Epitaxial Growth of Silicon Carbide on On-axis Silicon Carbide Substrates Using Methyltrichlorosilane Chemical Vapor Deposition
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Total Pages:
Release: 2008
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4H-silicon carbide (4H-SiC) is a wide band gap semiconductor with outstanding capabilities for high temperature, high power, and high frequency electronic device applications. Advances in its processing technology have resulted in large micropipe-free single crystals and high speed epitaxial growth on off-axis silicon face substrates. Extraordinarily high growth rates of high quality epitaxial films (>100 [Mu]m per hour) have been achieved, but only on off-axis substrates (misoriented 4° to 8° from the (0001) crystallographic plane). There is a strong incentive to procure an on-axis growth procedure, due to the excessive waste of high quality single crystal associated with wafering off-axis substrates. The purpose of this research was to develop a reliable process for homoepitaxial growth of 4H-SiC on on-axis 4H-SiC. Typically the use of on-axis SiC for epitaxial growth is undesired due to the increased probability of 3C-SiC inclusions and polycrystalline growth. However, it is believed that the presence of chlorine during reaction may reduce the presence of 3C-SiC and improve the quality of the epitaxial film. Therefore homoepitaxial SiC was deposited using methyltrichlorosilane (MTS) and ethane sources with carrier gases consisting of argon-hydrogen mixtures. Ethane was used to increase the C/Si ratio, to aid in the prevention of 3C-SiC, and to help eliminate silicon droplets deposited during epitaxial growth. Deposition occurred in a homemade, quartz, cold wall chemical vapor deposition reactor. Epitaxial films on on-axis 4H-SiC were deposited without the presence of 3C-SiC inclusions or polycrystalline SiC, as observed by defect selective etching, scanning electron microscopy and optical microscopy. Large defect free areas, [similar to]5 mm[superscript]2, with epitaxial film thicknesses of [similar to]6 [Mu]m were grown on on-axis 4H-SiC. Epitaxial films had approximately an 80%, [similar to]20 cm[superscript]-2, decrease in defect density as compared to the substrates. The growth rate was independent of face polarity and orientation of the substrate. The optimal temperature for hydrogen etching, to promote the smoothest epitaxial films for on-axis substrates (both C- and Si-polarities), is [similar to]1550 °C for 10 minutes in the presence of 2 slm hydrogen. The optimum C/Si ratio for epitaxial growth on on-axis 4H-SiC is 1; excess carbon resulted in the codeposition of graphite and cone-shaped silicon carbide defects.

Epitaxial Growth of Silicon on Poly-crystalline Si Seed Layer at Low Temperature by Using Hot Wire Chemical Vapor Deposition

Epitaxial Growth of Silicon on Poly-crystalline Si Seed Layer at Low Temperature by Using Hot Wire Chemical Vapor Deposition
Author: Manal Abdullah Aldawsari
Publisher:
Total Pages: 232
Release: 2015
Genre: Chemical vapor deposition
ISBN: 9781321697520

Crystallinity quality is a significant factor toward confirming the epitaxial layer. Raman scattering, X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), and Transmission Electron Microscope (TEM) were used to determine the crystallinity. Epitaxial growth of Si at 500 °C was obtained even with a low vacuum of 1x10-3 torr.

Epitaxial Growth and Optoelectronic Characterization of Cubic Silicon Carbide Deposited Using Chemical Vapor Deposition on Porous Silicon

Epitaxial Growth and Optoelectronic Characterization of Cubic Silicon Carbide Deposited Using Chemical Vapor Deposition on Porous Silicon
Author: Frederick Paul Vaccaro
Publisher:
Total Pages: 406
Release: 1999
Genre:
ISBN:

ABSTRACT: Cubic silicon carbide is a promising material for applications in high-power, high-frequency, high-temperature, and high-speed electronic devices. Fourier Transform Infrared Spectroscopy (FTIR), Secondary Ion Mass Spectrometry (SIMS), X-Ray Diffraction (XRD) and Atomic Force Microscopy (AFM) evaluations performed on thin films grown heteroepitaxially on porous (i.e. anodized) silicon using a new chemical vapor deposition (CVD) method employing trimethylsilane confirmed that the thin films were stoichiometric, cubic silicon carbide (3C-SiC). Conclusions were drawn on the basis of comparisons with published standards as well as with results generated on reference materials. SIMS profiles revealed the growth rates at approximately 1150̊C to vary from 2.1 to 4.0 Å/min. depending upon the slight variations in the CVD process trimethylsilane gas pressure. AFM evaluations revealed that the deposition mode at short deposition times was homo-oriented island nucleation and growth but that the 3C-SiC thin films evolved into continuous terraced layers at longer deposition times. Heterojunction (pn) junction diodes, fabricated from CVD and chemical vapor converted (CVC) porous silicon specimens, displayed world record breakdown voltages as high as 140 volts and 150 volts respectively. Historically, heterojunction (pn) junction diodes fabricated from 3C-SiC thin film specimens deposited on non-anodized displayed breakdown voltages below 10 to 20 volts.