US 5,495,122 A · Insulated-gate semiconductor field effect transistor which operates with a low gate voltage and high drain and source voltages

Abstract

In a low voltage drive circuit section of a semiconductor integrated circuit, the gate oxide films are approximately 250 .ANG., and a low voltage N-channel IGFET and a low voltage P-channel IGFET are operable at high speed and driven at a low voltage. In a high voltage driven circuit section, the gate oxide films are approximately 1500 .ANG., and a high voltage N-channel IGFET and a high voltage P-channel IGFET are designed to have a high breakdown voltage performance. In a low gate voltage/high voltage drive circuit section, the gate oxide films are approximately 250 .ANG., and a high voltage N-channel IGFET is driven at a low gate voltage and operable at high speed. The high voltage N-channel IGFET of the low gate voltage/high voltage drive circuit section has an offset structure including a drain diffusion layer of low concentration, such that the breakdown voltage of the drain is greatly increased.

Claims3

Dependent claims

A semiconductor integrated circuit comprising:

a first insulated gate semiconductor field effect transistor (IGFET) having a first gate, a first source, and a first drain operated with a low gate voltage level and a low source-drain voltage level;
a second IGFET having a second gate, a second source, and a second drain operated with a high gate voltage level substantially greater than the low gate voltage level and a high source-drain voltage substantially greater than the low source-drain voltage level;
and
a third IGFET having a third gate, a third source, and a third drain operated with the low gate voltage level on the third gate, and the high source-drain voltage level, said third IGFET having a high impurity drain region in a low impurity drain region, and a gate insulating film of the third IGFET is thinner than that of a gate insulating film of the second IGFET.

1 more element

Dependencies are inferred from the claim text.

Insulated-gate semiconductor field effect transistor which operates with a low gate voltage and high drain and source voltages

Life of this patent

Insulated-gate semiconductor field effect transistor which operates with a low gate voltage and high drain and source voltages

Life of this patent

Abstract

Claims3