| 摘要 |
<p>This high-voltage MOS transistor (semiconductor device) includes: a semiconductor substrate (1) having an n-type well region (2), a p-type source region (5), and a p-type drain region (6) formed therein; a gate oxide film (7) formed on the semiconductor substrate (1); and an isolation oxide film (3) provided between the drain region (6) and the gate oxide film (7). In the well region (2), a p-type first diffusion layer (4) is formed in a region including the regions below the isolation oxide film (3), and also an n-type second diffusion layer (11) is formed below the first diffusion layer (4) at a distance from the first diffusion layer (4). The impurity concentration of the first diffusion layer (4) is lower than the impurity concentration of the drain region (6), and the impurity concentration of the second diffusion layer (11) is higher than the impurity concentration of the well region (2).</p> |
