SEMICONDUCTOR ELEMENT AND ITS MANUFACTURE

PROBLEM TO BE SOLVED: To easily and surely prevent the occurrence of leakage currents due to bird's beaks, without making an element forming are smaller. SOLUTION: A semiconductor element is provided with an element separating area 6 formed by thermally oxidizing the surface of a silicon substrate 1 by the use of a silicon nitride film 3 formed on the surface of the substrate 1 via an oxide film 2 as a selective mask. On the surface of the silicon substrate 1 near the edges 3' of the silicon nitride film 3, impurity pre-diffused regions 7 formed by diffusion an impurity are provided. Therefore, the occurrence of leakage currents is prevented, by wrapping crystal defects generated in the substrate 1 due to bird's beaks in the sections 7.