Patent ID: 6217784
Filing Date: 2001-04-17
Classification: H01L

Abstract:
A process for forming a capacitor storage cell on a semiconductor substrate comprising the steps of:forming a first layer of a silicon oxide on the surface of said substrate;forming a second layer of a silicon oxide on said first layer of silicon oxide, said first silicon oxide being relatively more dense than said second silicon oxide;forming an opening into said first and second silicon oxide layers;forming a polysilicon or amorphous silicon container structure having generally vertically-oriented side walls in said opening;selectively removing at least a portion of said second silicon oxide layer by exposing said second silicon oxide layer to a liquid comprising a halide-containing species;selectively removing the remainder of said second silicon oxide layer by exposing said second layer to a gas phase comprising a halide-containing species, thereby exposing the side walls of said container structure;without exposing said substrate to oxygen or an oxygen-containing gas, annealing said container walls at an elevated temperature to transform said polysilicon or amorphous silicon into hemispherical grain silicon;conductively doping said hemispherical grain silicon walls to form capacitor plates;forming a capacitor dielectric layer over said capacitor plates; andforming a second conductive silicon layer over said capacitor dielectric layer.