Patent ID: 7232718
Filing Date: 2007-06-19
Classification: H01L

Abstract:
1. A method for forming a deep trench capacitor buried plate comprising: providing a substrate having a pad oxide layer and a pad nitride layer thereon, the pad oxide layer and the pad nitride layer having at least an opening; performing a dry etching process for forming a deep trench in the substrate via the opening; depositing a doped silicate glass film on an inner wall of the deep trench; filling a sacrificial layer into the deep trench; etching back the sacrificial layer for exposing parts of the doped silicate glass film; removing the exposed doped silicate glass film; removing the remaining sacrificial layer; depositing a silicon nitride layer on the inner wall of the deep trench; performing a thermal process for forming a doped region at a bottom of the trench after the remaining sacrificial layer is removed; removing the silicon nitride layer; and removing the doped silicate glass film; wherein the silicon nitride layer serves as a barrier layer for preventing ions of the doped silicate glass film from diffusing into a collar region of the deep trench.