Method for forming the gate insulator of a MOS transistor
AssigneeSTMicroelectronics (Crolles 2) SAS
InventorsOlivier Gourhant, David Barge, Clément Gaumer, Mickaël Gros-Jean
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Abstract
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.
Claims7
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.
Dependencies are inferred from the claim text.