Abstract: Multiple oxide layers with different thicknesses are formed on a semiconductor substrate with a silicon surface, having a first and second region. A sacrificial oxide layer is formed on the silicon surface to cover both the first region and the second region, with a mask layer formed on the surface of the sacrificial oxide layer. By defining and patterning the mask layer, a first opening and a second opening, having predetermined surface areas, are formed in portions of the first and second regions of the mask layer to expose portions of the. The sacrificial oxide layer has a surface area equal to the first predetermined surface area, and portions of the sacrificial oxide layer having a surface area equal to the second predetermined surface area. A linear nitrogen doping process is then performed to simultaneously implant nitrogen ions with a first and second predetermined concentration into the first and second region, through the first opening and the second opening, respectively.

Abstract: A method for manufacturing an integrated circuit device includes forming a multi-layer film, such as an ONO film, on a surface of the substrate, the multi-layer film including the first layer of silicon oxide, a middle layer of silicon nitride, and a top layer of silicon oxide. The top layer of silicon oxide has an exposed surface. Next, the process involves exposing the exposed surface of the top layer of the multi-layer film to a plasma containing nitrogen radicals, to form a nitrided layer of oxide on the exposed surface. The nitrided layer of oxide on the top layer of silicon oxide in the multi-layer film has a thickness sufficient to protect the multi-layer film from damage during subsequent cleaning steps, used for example to prepare the substrate for formation of gate oxides in regions remote from the multi-layer film.