| 摘要 |
<p>A method for manufacturing an extended drain MOS transistor is provided to reduce a design rule by reducing a drain extension region by increasing a threshold voltage by forming a thin gate oxide film on the drain extension region. A diffusion preventing layer(104) is formed on a semiconductor substrate(102). A first conductive epitaxial layer is formed on the diffusion preventing layer. A gate oxide layer is formed in a first conductive epitaxial layer. A thin gate oxide layer(118a) is formed by patterning the gate oxide layer. A second conductive epitaxial layer is formed on the first conductive epitaxial layer. The gate oxide layer is formed by a wet oxidation process. The thin gate oxide layer is formed by using a photoresist layer as an etching mask. The hard mask layer is made of one of SiO2, SiN, or Si3N4.</p> |
