Diffusion of implanted dopant and polysilicon oxidation processes for VDMOS.

摘要

In order to eliminate unwanted crystal defects generated by an ion implantation, a semiconductor substrate (110) or an epitaxial layer (101), which is selectively subjected to an impurity ion implantation (107), is heat-treated in an inert gas atmosphere at 850 to 1050 DEG C to recrystallize the implanted region (108). Thereafter, the semiconductor substrate (110) is heat-treated at 900 to 1250 DEG C in an atmosphere containing oxygen. For eliminating abnormal growth of grain boundaries in a polycrystalline semiconductor layer (105, 105 min ) deposited on an insulating film (103, 104), the semiconductor layer (105, 105 min ) is heat-treated at 900 to 1100 DEG C in an atmosphere containing oxygen. By applying at least one of these processes to usual fabrication methods, semiconductor devices with high reliability such as power MOSFETs will be provided.