The effects of implant activation anneal on the effective inversion layer mobility of 4H-SiC MOSFETs

In this paper, we investigate the effective inversion layer mobility of lateral 4H-SiC metal oxide semiconductor field-effect transistors (MOSFETs). Initially, lateral n-channel MOSFETs were fabricated with three process splits to investigate phosphorus implant activation anneal temperatures of 1200, 1650, and 1800 degrees C. Mobility results were similar for all three temperatures (using a graphite cap at 1650 degrees C and 1800 degrees C). A subsequent experiment was performed to determine the effect of p-type epi-regrowth on the highly doped p-well surface. The negative effects of the high p-well doping are still seen with 1500 angstrom p-type regrowth, while growing 0.5 mu m or more appears to be sufficient to grow out of the damaged area. A continuing series of tests are being conducted at present.