SEMICONDUCTOR ELENENT MANUFACTURING METHOD

摘要

PURPOSE: A method for fabricating a semiconductor device is to induce a free electron or positive ion at a surface of a trench for device isolation, thereby decreasing a leakage current. CONSTITUTION: A trench is respectively formed at a P-well region and an N-well region of a semiconductor substrate. The semiconductor substrate including the trench is oxidized and thus the first oxidation layer is formed on the surface of the semiconductor substrate including the trench. A negative fixed oxidation charge is accumulated in the first oxidation layer of the P-well region. A positive fixed oxidation charge is accumulated in the first oxidation layer of the N-well region. The trenches are filled with the second oxidation layer by a CVD method. The resultant substrate is etched back until the surface of the semiconductor substrate is exposed.