Method of forming dual gate oxide layers of varying thickness on a single substrate

Abstract

A method for manufacturing a semiconductor device that includes dual gate oxide layers made of two dielectric layers of varying thickness on a single wafer. In an example embodiment, a semiconductor structure is fabricated by providing a first layer of a dielectric over a semiconductor material and covering the first layer with a protective second dielectric layer adapted to mask the first layer. The first and second layers are then removed over a region of the semiconductor material while the second layer is used to protect the first layer, therein leaving the region of semiconductor material substantially exposed. A third layer of dielectric material is formed over the first and second layers and the adjacent exposed semiconductor material region; a gate material is then formed over the third dielectric layer. Finally, an etching step etches through the gate material and underlying layers to the semiconductor material to form a thick gate region and a thin gate region. The thick and thin gate regions can be formed on the same substrate using substantially the same manufacturing process.