US 5,847,432 A · Semiconductor device and production method therefor

Abstract

A semiconductor device to which two kinds of electric voltage can be supplied comprises: a first MOS transistor formed in the first well having a first conduction type and being fixed to a first electric potential, a second MOS transistor formed in a second well having a second conduction type different from the first one and being fixed to a second electric potential higher than the first electric potential, and a third well formed between the first and second wells having the second conduction type and being fixed to a ground electric potential. The first MOS transistor comprises a first gate oxide film having a prescribed thickness and a first gate electrode having a prescribed gate length, while the second MOS transistor comprises a second gate oxide film having a thickness larger than the prescribed thickness of the first gate oxide film and a second gate electrode having a gate length longer than the prescribed thickness of the first gate length.

Claims9

Dependent claims

A semiconductor device comprising:

a semiconductor substrate;
a first complementary MOS transistor formed in said semiconductor substrate, said first complementary MOS transistor being driven under a first power supply voltage;
a second complementary MOS transistor formed in said semiconductor substrate, said second complementary MOS transistor being driven under a second power supply voltage higher than the first power supply voltage;
and
a well formed between said first and second complementary MOS transistors in said semiconductor substrate, said well being fixed to a prescribed voltage.

2 more elements

A method for fabricating a semiconductor device comprising the steps of:

forming a plurality of islands in a semiconductor substrate for defining first to fifth regions successively in the semiconductor substrate;
injecting first ions into the second and fourth regions to form second and fourth wells having a first conduction type;
injecting second ions different from the first ions into the first, third and fifth regions to form first, third and fifth wells;
injecting further ions into the first and second regions so as to make a threshold voltage of MOS transistors to be formed in the first and second regions the same as those of MOS transistors to be formed in the fourth and fifth regions;
forming a first complementary MOS transistor in the first and second wells;
forming an electrode in the third well to be fixed to a ground potential;
and
forming a second complementary MOS transistor in the fourth and fifth wells to which a power supply voltage higher than that of the first complementary MOS transistor is applied.

5 more elements

Dependencies are inferred from the claim text.

Semiconductor device and production method therefor

Life of this patent

Semiconductor device and production method therefor

Life of this patent

Abstract

Claims9