Ultrathin Vertical Gate Oxide for Trench Power Device Technology

In this work, we had successfully demonstrated the feasibility of growing an ultrathin 50 Å vertical trench gate oxide with a very good intrinsic dielectric breakdown strength, exceeding 9 MV/cm, and also an excellent reliability performance of zero ppm. To achieve this, prior to gate oxidation, it is crucial to minimize both trench sidewall roughness and trench top corner sharpness. These two parameters are important to prevent the intensification of resultant local electric field and the possible generation of interface trap states which are responsible for vertical gate oxide degradation in power devices.