Optimisation of Selective Polysilicon Oxidation for 0.8μm-Technology

The dependence of bird´s beak length on process parameters has been studied for selective polysilicon oxidation. The gate oxide thinning at the field oxide edge is correlated with the voltage drop across the gate oxide for constant current stress. We show, that with an optimised set of process parameters the bird´s beak length can be reduced to 0.15μm without deteriorating device reliability.