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

Abstract

Channel mobility of >100 cm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{2}$ </tex-math></inline-formula> V <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{-1}$ </tex-math></inline-formula> s <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{-1}$ </tex-math></inline-formula> has 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.