Silicon Carbide: the Premier Paradigm for Structural and Microelectronic Device Applications in Severe Environments

Abstract

ABSTRACTThe extreme thermal, mechanical, corrosion resistant and electronic properties of SiC provide multiplicative combinations of attributes which allow a variety of products for very different applications. The emphasis herein will be the consideration of both the constant stress creep properties of several types of polycrystalline SiC materials and the characteristics of different SiC-based devices having high power, high frequency and switching applications and which are operational at ≥573K. The controlling mechanism in reaction-bonded SiC within the ranges of temperature and stress of 1848K-1923K and 110–220 MPa, respectively, is glide/climb controlled by climb. The controlling creep mechanism in CVD material at T<1873K is dislocation glide controlled by the Peierls stress; above this temperature, the evidence suggests that dislocation glide/climb controlled by climb becomes an increasingly important mechanism. For sintered α-SiC within the respective temperature and stress ranges of 1670K-2073K and 138–414 MPa, the controlling creep mechanisms are grain boundary sliding accommodated by grain boundary diffusion at T<1800K and lattice diffusion at T> 1920K. By contrast, the continual development of SiC thin film deposition and the device related technologies of doping, contacts and dry etching have culminated in a host of microelectronic devices operable at high temperatures, namely, MOSFET high power devices, MESFET high frequency devices, and switches including p-n junctions and thyristors. The properties of selected devices and circuits made from them are described with an emphasis on their operation at high temperature.