| 摘要 |
<p>A method for forming a semiconductor device having an isolation trench (14) for separation of element regions includes the steps of forming a pad oxide film (12) and a silicon nitride film (13) on a silicon substrate (11), forming an isolation trench (14) by using the silicon nitride film as a mask, forming consecutively a thermal oxide film (15), CVD oxide film (16) and a bias oxide film (17) in the isolation trench (14), removing the films above a specified level of the silicon substrate (11) to leave the isolation trench (14) filled with oxide films (15,16 and 17). The bias oxide film (17) is formed by a high-density plasma CVD technique. The silicon surface is protected by the CVD oxide film (16) against the plasma damage during the high-density CVD step, thereby obtaining excellent characteristics of transistors. <IMAGE></p> |
