Patent ID: 9455136
Filing Date: 2016-09-27
CPC Classification: H01L

Claim Text:
1. A method for depositing an insulating layer, the method comprising: performing a primary deposition over a first sidewall of a feature and a second sidewall of the feature by depositing a layer of silicate glass using a silicon source at a first flow rate and a dopant source at a second flow rate, wherein a ratio of the flow of the dopant source to the flow of the silicon source is a first ratio, wherein the second sidewall faces the first sidewall, and wherein the first sidewall intersects with the second sidewall at acute vertices and the feature comprises a trench gate disposed in a substrate, a common drain in the substrate, and a source region coupled to a contact pad; performing a secondary deposition over the first sidewall of the feature by increasing the flow of the silicon source relative to the flow of the dopant source, wherein the ratio of the flow of the dopant source to the flow of the silicon source is a second ratio lower than the first ratio; stopping the flow of the silicon source after performing the secondary deposition; and performing a reflow process after stopping the flow, wherein, after the reflow process, a variation in thickness of the layer of silicate glass at the acute vertices and other regions of the layer of silicate glass over the sidewall is between 0.1% to 10%, wherein the first sidewall and the second sidewall contact the trench gate, wherein the first sidewall intersects with the second sidewall at an angle less than 60° inside the trench.