US 7,452,774 B2 · Semiconductor device including transistor with composite gate structure and transistor with single gate structure, and method for manufacturing the same

Abstract

A semiconductor device comprises a first transistor having a composite gate structure containing a lamination of a first polycrystalline silicon film, an interlayer insulating film, and a second polycrystalline silicon film; and a second transistor having a single gate structure containing a lamination of a third polycrystalline silicon film and a fourth polycrystalline silicon film, wherein the first polycrystalline silicon film and the third polycrystalline silicon film have substantially the same thickness; the first polycrystalline silicon film and the third polycrystalline silicon film have different impurity concentrations controlled independently of each other; the second polycrystalline silicon film and the fourth polycrystalline silicon film have substantially the same thickness, and the second polycrystalline silicon film, the fourth polycrystalline silicon film, and the third polycrystalline silicon film have substantially the same impurity concentration. Also, a method for manufacturing the above-described semiconductor device is described.

Claims21

Dependent claims

A method of manufacturing a semiconductor device having a first region and a second region, the method comprising:

forming a first oxide film on a substrate in the first region;
forming a second oxide film on the substrate in the second region;
forming a first conductive layer over a portion of the substrate that includes at least the first oxide film and the second oxide film;
introducing impurities into the first conductive layer;
forming a first insulating layer over the first conductive layer;
removing at least a portion of the first insulating layer over the second region;
forming a second conductive layer over at least a portion of the substrate such that the first and second conductive layers are separated by the first insulating layer in the first region and the first and second conductive layers are at least partially in contact with each other over their cross-sections in the second region;
and
introducing impurities into the second conductive layer such that the second conductive layer has a conductivity that is higher than the first conductive layer in the first region, and such that the first and second conductive layers have substantially the same conductivity in the second region.

6 more elements

Dependencies are inferred from the claim text.

Semiconductor device including transistor with composite gate structure and transistor with single gate structure, and method for manufacturing the same

Life of this patent

Semiconductor device including transistor with composite gate structure and transistor with single gate structure, and method for manufacturing the same

Life of this patent

Abstract

Claims21