METHOD FOR MANUFACTURING SEMICONDUCTOR DEVICE

摘要

PURPOSE: A fabrication method of semiconductor devices is provided to improve GILD(Gate Induced Lateral Diffusion) and to reduce thermal budget by rounding at edge portions of a trench. CONSTITUTION: After forming a trench at a gate formation region of a semiconductor substrate(21), a gate oxide layer(23) is formed on the trench by performing oxidation processing. At this time, the edge portions of the trench are rounded, so that the thickness of the gate oxide layer(23) is thick. A gate electrode(25) is formed on the gate oxide layer(23). An LDD(Lightly Doped Drain) region(26) is then formed in the semiconductor substrate(21). Then, a spacer(27) is formed at both sidewalls of the gate electrode(25).