As the demands on electronic systems intended for high temperature, high power or high frequency operation increase, silicon-based electronics are being pushed to its fundamental material limits. Consequently, continued improvement in system level performance for these applications requires new semiconductor materials. Silicon carbide (SiC) is a candidate material for the applications listed above, but considerable materials, processing, and device research are still needed before SiC devices are brought to market.
This paper concentrates on ion implantation processing of SiC, and attempts to illustrate specific problems associated with ion implantation. Data from a series of experiments relevant to SiC MOSFETs are presented for this purpose. Ion implants into SiC are discussed first to show how a strategy for improving the acceptor activation ratio from less than 1% to nearly 100% is developed. The annealing temperatures (>1600°C) needed to attain high activation ratios lead to severely roughened surfaces. Results from experiments designed to preserve high-quality surfaces have been encouraging from a purely materials perspective. However, these solutions do not translate into improved transport characteristics for SiC MOSFETs. An investigation of inversion layer mobility in 4H-SiC MOSFETs is presented to illustrate this point.