Patent ID: 6258694
Filing Date: 2001-07-10
Classification: H01L

Abstract:
A fabrication method of a device isolation structure, comprising:forming a patterned mask layer on a silicon substrate;performing a first doping step using the patterned mask layer as a first mask to dope a portion of the silicon substrate exposed by the first mask with a first dopant in order to inhibit an oxidation of the silicon;forming a spacer on a sidewall of the mask layer;removing portions of the silicon substrate to form a trench with the mask layer and the spacer serving as a second mask;performing a second doping step to dope a portion of the silicon substrate exposed by the second mask at a bottom of the trench with a second dopant in order to benefit an oxidation of the silicon, wherein the second dopant comprises oxygen; andperforming a field oxidation step to form a field oxide layer in the trench and to fill the trench.