| 摘要 |
PROBLEM TO BE SOLVED: To obtain a method for manufacturing a semiconductor device which can avoid deterioration of the operational characteristics of a semiconductor element isolated by element isolation regions of a trench isolation structure even when made fine. SOLUTION: Ions 15 are implanted upwards onto a silicon nitride film 2 into a polycrystalline silicon layer 3 to obtain an ion-implanted polycrystalline silicon layer 16. Since the ions 15 are ion species of an element having enhanced oxidation action, the implantation of the ions 15 causes conversion from the polycrystalline silicon layer 3 to the ion-implanted polycrystalline silicon layer 16 having a higher oxidation rate. Thereafter, at the time of forming a thermal oxidation film 21 on an inner wall of a groove 5, an exposed part of the silicon layer 16 is also oxidized so that a polycrystalline silicon oxidation region 21a is formed relatively wide.
|
