Method for fabricating oxide layers with different thicknesses

摘要

A method for fabricating oxide layers with different thicknesses on a substrate is described. A field oxide layer is formed on the substrate to define a first active region and a second active region therebetween. A first oxide layer is formed over the first active region. A thin oxynitride layer is formed on the first oxide layer. The substrate is oxidized to form a second oxide layer over the second active region, wherein the second oxide layer has a thickness different from the thickness of the first oxide layer,