Patent ID: 6025234
Filing Date: 2000-02-15
Classification: H01L,Y10S

Abstract:
A method for forming devices having a thick gate oxide, such that thin gate oxide devices and thick gate oxide devices are formed respectively over a first device area and a second device area previously defined on a substrate, comprising the steps of:forming a first gate oxide layer over the substrate;depositing a silicon nitride layer over the first gate oxide layer;depositing a photoresist layer over the silicon nitride layer;patterning the photoresist layer with a mask, then etching away portions of the silicon nitride layer to expose the entire first gate oxide layer above the second device area;thermally growing an oxide layer over the first gate oxide layer in the second device area such that the thermally grown oxide layer together with the first gate oxide layer forms a second gate oxide layer; andremoving the silicon nitride layer above the first device area.