| 摘要 |
<p>PROBLEM TO BE SOLVED: To reduce the parasitic capacitance in isolated regions to ensure a high speed operation by forming an ion implanting mask film covering trench side faces, using a film contg. silicon nitride. SOLUTION: An Si single crystal substrate provides a p-type semiconductor region 1 on which an n-type epitaxial layer-made n-type semiconductor region 2 is formed with an oxide film 3 formed on the surface of this region 2. By the low pressure CVD, a nitride film 4 is formed on the oxide film 3, and by the ordinary pressure CVD an oxide film 5 is laminated on the nitride film 4. By the photolithography the oxide film 5, 3 and nitride film 4 are etched away to expose the surface of the n-type semiconductor region 2. Using the oxide film 5 as a mask, trenches 6 reaching the p-type semiconductor region 1 are formed. After removing the oxide film 5, the bottoms and side faces of the trenches 6 are covered with an oxide film and film contg. Si nitride is formed thereon.</p> |
