The premier research laboratory in the DoD for exploration of growth of the wide bandgap semiconductor silicon carbide (SiC) using high-temperature chemical vapor deposition and a hot-walled geometry. Current research aims at establishing tight control of point and extended defects in thick epitaxial layers for use in high-voltage, high-current power electronic devices. Research activities range from basic research studies of materials and crystal growth to more applied investigations involving devices.
Homoepitaxial growth of SiC layers on SiC substrates is accomplished by the reaction of silane and propane at temperatures between 1500º and 1800º C and pressures of 50-200 mbar. Growth rates are varied from 2 µm/hr to 15 µm/hr. The crystal quality is a direct function of the substrate preparation and growth conditions used, such as the ratio of carbon to silicon atoms in the gas phase. The epilayers can be doped either n- or p-type from 1 x 1014 cm-3 to 5 x 1018 cm-3 using dopants such as nitrogen or aluminum, respectively. In situ growth monitoring with mass spectrometry and laser-based reflectance techniques permits study of the growth environment. Through knowledge gained from these studies and control of the growth process, different types of complex structures can be grown. The equipment is housed in a specially designed and constructed laboratory space for the chemicals used in the growth process.
The laboratory comprises two adjacent facilities: the Growth Facility and the Immediate Characterization Facility. The Growth Facility is centered about an Epigress/Aixtron VP508 high-temperature chemical vapor deposition reactor that is widely used in the SiC community to deposit homoepitaxial SiC epilayers on SiC substrates. The Immediate Characterization Facility hosts tools that permit researchers to rapidly characterize epitaxial wafers, providing feedback to growth efforts.