Optimization of trench sidewall for low leakage current of the sloped field plate trench edge termination

In this paper, trench sidewall optimization of the sloped field plate trench edge termination structure for low leakage current is experimentally conducted. It is found that the leakage current is highly dependent on the trench sidewall treatment. Rough trench sidewall results in large stress during trench sidewall oxidation, leading to large leakage current. Smooth trench sidewall and a thin layer of thermal oxide should be applied to the trench for achieving a significantly lower leakage current.