Influence of trench etching on super junction devices fabricated by trench filling

We have proposed a fabrication method for super junction (SJ) diodes with low leakage current characteristics by using a wet anisotropic trench etching and Si(111) oriented trench epitaxial filling processes. The SJ diodes show electrical characteristics with a breakdown voltage of 225 V and a leakage current density below 1×10^-7 A/cm². By experimental comparisons between three types of SJ diodes of the [111] oriented trench, formed by wet anisotropic etching, and [111] and [010] oriented trenches formed by the conventional reactive ion etching (RIE) process, we have clarified an effect of the wet etching process on the lower leakage characteristics of the trench filling SJ diode.