| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of isolating elements of semiconductor deice. SOLUTION: An insulation film for mask is formed on a predetermined area of a semiconductor substrate 100, and a trench 110 having a predetermined depth is formed using the insulation film for mask. Oxide films 105 and 107 are formed on a side wall of the insulation film for mask and an inner wall of the trench, and a trench liner film 109 is formed thereon. Then insulation film 111 for filling is formed such that the trench is fully filled. Subsequently, the insulation film for mask is removed. In this manner, in the method of isolating trench type devices, the formation of oxide film also on the side wall of the insulation film for mask after etching the trench of the semiconductor substrate allows preventing a depression which tends to occur on both sides of the trench, and a phenomenon of bird's beak type osmosis of oxide film which occurs at an interface touching the mask insulation film, reducing and controlling leakage current to improve characteristic of threshold voltage. |
