Method of forming double gate dielectric layers and semiconductor device having the same

Abstract

A method of forming double gate dielectric layers composed of an underlying oxide layer and an overlying oxy-nitride layer is provided to prevent degradation of gate dielectric properties due to plasma-induced charges. In the method, the oxide layer is thermally grown on a silicon substrate under oxygen gas atmosphere to have a first thickness, and then the oxy-nitride layer is thermally grown on the oxide layer under nitrogen monoxide gas atmosphere to have a second thickness smaller than the first thickness. The substrate may have a high voltage area and a low voltage area, and the oxide layer may be partially etched in the low voltage area so as to have a reduced thickness. The oxy-nitride layer behaves like a barrier, blocking the inflow of the plasma-induced charges.

Dependencies are inferred from the claim text.