Semiconductor device

Abstract

Abstract PURPOSE: To enable the microminiaturization of a well layer formed in a semiconductor substrate at the boundary of the well layer by forming a high density diffused layer in the boundary of the well layer in a C-MOS structure, thereby preventing the decrease in the punch-through withstand voltage between the substrate and the well. CONSTITUTION: A resist film 25 having a hole is covered on a part in the vicinity of a boundary A on a P type well 23 on an N type Si substrate 21 formed with the well 23, ions are implanted with the film 25 as a mask, and a P type region 26 having a density higher than the well 23 is formed. Thereafter, inversion preventive layers 30, 31 are formed with an ordinary method, and a thick oxidized film 32 is formed thereon. In this state, an N-channel MOS is formed on a P type well 23, a P channel MOS is formed on the substrate 21, is wired with an aluminum layer 42 to form a C-MOS. Since high density P type layer 26 is disposed between the N + type drain region 38 and the substrate 21, the extension of a depletion layer is suppressed, thereby improving the punch-through withstand voltage. The element can be formed that much in the vicinity of the boundary. COPYRIGHT: (C)1982,JPO&Japio

Inventors

• 👤 Takeo Kondo

Bibliographic Details