The effect of nitrogen plasma anneals on interface trap density and channel mobility for 4H–SiC MOS devices

We report results on the introduction of nitrogen at the SiC/SiO2 interface using a plasma process, thus avoiding the detrimental effects of additional oxidation that accompany other standard nitridation processes, such as annealing in NO gas. The plasma process results in an ‘NO-like’ mobility for approximately 1/6 the interfacial nitrogen content injected via the gas anneal. Direct exposure of the oxide to the plasma is also shown to have a deleterious effect on the breakdown characteristics of the oxide.

Research highlights
► Use a nitrogen plasma to successfully introduce nitrogen into SiO2/SiC interface.
► N Conc. at the interface is 1 × 1014 cm−2, ∼1/6 of the saturated N Conc. by NO anneal.
► This process reduces DIT and results in peak channel mobility at about 50 cm2/V s.