METHOD FOR FORMING FIRST OXIDE LAYER, AND SECOND OXIDE LAYER

• Main Authors: FULFORD H JIM JR, GARDNER MARK I
• Format: Patent
• Language: English
• Published: 07.02.2008
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; SEMICONDUCTOR DEVICES

PROBLEM TO BE SOLVED: To provide a method for improving the quality of an extremely thin oxide layer. SOLUTION: A high-quality tunnel oxide film, suitable for programmable devices, such as EEPAL devices, is formed on a surface region of a semiconductor body over a heavily-doped N+ layer, and a gate oxide film is formed over a gate region, by first oxidizing the semiconductor body to form an initial oxide layer (104) on the surface region of the semiconductor body over the heavily-doped N+ layer and on the surface of the gate region. Next, at least a portion of the initial oxide layer (104), overlying the heavily-doped N+ layer, is removed. The semiconductor body is then exposed to an environment suitable for oxidation, to thicken the remaining portions of the initial oxide film, thereby forming the gate oxide film, and to form the tunnel oxide film over the heavily doped N+ layer. A certain concentration of nitrogen is introduced into both gate and to tunnel oxide films, by introducing the semiconductor body to a source of nitrogen. COPYRIGHT: (C)2008,JPO&INPIT