Manufacture of insulated gate type field effect transistor

Abstract

Abstract PURPOSE:To increase the withstand voltage between the source and the drain in a field effect transistor by forming the source region and the drain region forming an IGFET of a high impurity density region and a low impurity density region contacted with the high impurity density region, thereby suppressing the expansion of a depletion layer. CONSTITUTION:A thick field oxidized film 2 is formed at the peripheral edge of an Si substrate 1, a gate SiO2 film 3a is covered on the surrounded substrate 1 with the film 2, and a polycrystalline Si layer 4a is accumulated as the gate electrode material on the overall surface. Then, a photoresist mask 7 of the prescribed pattern is formed thereon, is overetched to from a gate electrode 4, and an undercut region 8 is formed at the periphery. Thereafter, the film 3a of the exposed part is removed, reverse conductive type high impurity density are injected to the substrate 1 by utilizing the mask 7 extending in an overhang, and high density source and drain regions 5a, 5b are formed in the substrate 1. Then, the mask 7 is removed, and low density regions 5a, 5b are formed at the region 8 adjacent to these regions.

Inventors

• 👤 Isao Nishimura

Bibliographic Details