Method for forming the gate insulator of a MOS transistor

摘要

A method for forming the gate insulator of a MOS transistor, including the steps of: a) forming a thin silicon oxide layer at the surface of a semiconductor substrate; b) incorporating nitrogen atoms into the silicon oxide layer by plasma nitridation at a temperature lower than 200° C., to transform this layer into a silicon oxynitride layer; and c) coating the silicon oxynitride layer with a layer of a material of high dielectric constant, wherein steps b) and c) follow each other with no intermediate anneal step.

主权项

1. A method for forming the gate insulator of a MOS transistor, comprising the steps of:
a) forming a thin silicon oxide layer at the surface of a semiconductor substrate; b) incorporating nitrogen atoms into the silicon oxide layer by plasma nitridation at a temperature lower than 200° C., to transform the silicon oxide layer into a silicon oxynitride layer comprising a nitrogen atom concentration greater than 1×1014 atoms/cm2; and c) coating the silicon oxynitride layer with a layer of a material of higher dielectric constant than silicon oxynitride, wherein steps b) and c) follow each other with no intermediate anneal step, and wherein step a) comprises the forming, by chemical deposition, of the silicon oxide layer, followed by a rapid thermal oxidation at a temperature ranging between 800 and 1,200 degrees C.