Silicon carbide chemical vapor deposition, in situ doping and device fabrication

There is a great demand for wide bandgap semiconductors for high temperature, high power, high frequency, and optoelectronic applications. Due to its excellent thermal, chemical and electrical properties, as well as a large bandgap, silicon carbide (SiC) is a good candidate for the fabrication of devices designed for operations at high temperature and high power. Its high electron drift velocity enables SiC devices to operate in the high frequency regimes. Though the development of silicon carbide started in the 1950's, there are still numerous issues that must be resolved before SiC can attain its prominence as the material of choice for the fabrication of advanced devices to operate in harsh environments.; Chemical vapor deposition (CVD) is a commonly utilized method for epitaxial growth of active device epilayers. CVD epitaxial growths of various silicon carbide polytypes (3C-, 6H, and 4H-SiC) are the focus of this study. Due to the large lattice mismatch between 3C-SiC and silicon, special growth techniques must be applied to grow single crystal 3C-SiC on silicon. Effects of different growth procedures on film morphology and defect structures were studied. The mechanisms of formation of etch pits in 3C-SiC LPCVD samples were also investigated. Different growth techniques were implemented in an attempt to suppress etch pit formation. The defect structures and their formation were also studied in CVD-grown 6H- and 4H-SiC epilayers.; The suitability of the SiC epilayers for device applications depends on the quality of the epilayers. With the help of several collaborators, the quality of SiC epilayers was characterized using various techniques, such as X-Ray diffraction, Raman scattering, Fourier transform infrared spectroscopy (FTIR), X-Ray photoelectron spectroscopy (XPS), capacitance-voltage (C-V), current-voltage (I-V), and deep level transient spectroscopy (DLTS).; We have also characterized the growth rate and in situ doping of silicon carbide epilayers. The parameters affecting the doping concentrations were identified, and these parameters were used to control the doping process. The doping capability enables active device layers to be grown and doped in situ by CVD. Devices such as high power p-n junction diodes, blue light emitting diodes and MESFETs were fabricated on 4H-SiC epilayers demonstrating the capability of the CVD system to produce device quality epilayers.