| 摘要 |
PURPOSE:To prevent the occurrence of bird's beak and crystal defect and to attain high integration by a method wherein a film of silicide of high-melting metal is deposited to form a double layer structure when a polycrystalline silicon film is left only in a groove part, and the surface is oxidized with the polycrystalline silicon film left inside the groove. CONSTITUTION:With an oxide film 3 and tungsten silicide film 2 used as mask films, a groove 5 having a width W and a depth (d) and being vertical to the surface of a silicon substrate is formed in the silicon substrate 1 by an RIE method. Next, a layer 6 in which impurity ions are implanted is formed in the bottom portion of said groove 5. High-temperature oxidation is applied to the inner wall of the groove 5 to make an oxide film 7 grow. Then, a polycrystalline silicon film 9 is deposited so that the thickness (t) is t>=W/2. Subsequently, the polycrystalline silicon film 9 is etched back so that it is left only in the groove 5. The oxide film 3 is etched by using a 5% fluoric acid solution, and high-temperature oxidation is applied, so as to form an oxide film 11. Then, the oxide film 11 on the surface is etched until the tungsten silicide film 2 appears, and the tungsten silicide film 2 on the surface of the silicon substrate is removed. Thereafter, an element is formed by a conventional MOS process.
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