Investigation of the gate dielectric oxidation treatment in trench gate power devices

In respect of trench gate power devices, it is difficult to achieve satisfactory gate oxide leakage current, breakdown voltage and reliability characteristics. Trench etching process induced silicon surface damage, convex corner and contamination, which will degrade the silicon dioxide quality. It is convinced that post etching treatment including sacrificial oxidation and chemical dry ashing can improve the gate oxide quality significantly. In this article, we study the treatment of a trench capacitor with sacrificial oxidation and classify the effect of each parameter in the oxidation process. The benefit of N₂O annealing after gate oxidation will also be discussed. The evaluations of I-V and CV characteristics are the main considerations of the gate oxide quality in this research.