The Effects of Implant Activation Anneal on the Effective Inversion Layer Mobility of 4H-SiC MOSFETs

Abstract

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°C. Mobility results were similar for all three temperatures (using a graphite cap at 1650°C and 1800°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 A p-type regrowth, while growing 0.5 μm or more appears to be sufficient to grow out of the damaged area. A continuing series of tests are being conducted at present.