High Channel Mobility 4H-SiC MOSFETs by Antimony Counter-Doping

Channel mobility of >100 cm²V⁻¹s⁻¹has been obtained on enhancement mode 4H-SiC MOSFETs using an antimony (Sb) doped surface channel in conjunction with nitric oxide (NO) postoxidation annealing. Temperature dependence of the channel mobility indicates that Sb, being an n-type dopant, reduces the surface electric field while the NO anneal reduces the interface trap density, thereby improving the channel mobility. This letter highlights the importance of semiconductor/dielectric materials processes that reduce the transverse surface electric field for improved channel mobility in 4H-SiC MOSFETs.