METHOD FOR FABRICATING AN INTEGRATED SEMICONDUCTOR CIRCUIT
First Claim
1. A method for fabricating an integrated semiconductor circuit, which comprises:
- depositing a first layer sequence onto a semiconductor substrate, the first layer sequence having a bottommost layer composed of an oxidizable material;
patterning the first layer sequence by anisotropic etching in a first area region of the semiconductor substrate to form first gate structures having sidewalls and top sides, surfaces of the semiconductor substrate lying parallel to the top sides being defined between the gate structures, and removing the first layer sequence in a second area region of the semiconductor substrate;
oxidizing the bottommost layer of the first layer sequence at the sidewalls of the first gate structures in the first area region;
covering, in the first area region, at least the top sides of the first gate structures and the surfaces of the semiconductor substrate with an etch stop layer;
covering the first gate structures of the first area region by depositing a second layer sequence onto the semiconductor substrate;
patterning the second layer sequence by anisotropic etching of the second layer sequence to form second gate structures in the second area region and removing the second layer sequence from the first gate structures in the first area region, and stopping the removing of the second layer sequence in the first area region with the etch stop layer.
4 Assignments
0 Petitions
Accused Products
Abstract
Integrated semiconductor circuits have MOS transistors whose gate electrodes are provided with dopings in order to set the electrical potential of the channel region by an altered work function of the electrons. Transistors in semiconductor circuits having both a memory region and a logic region are fabricated either with different dopings for pMOS and nMOS transistors in the logic region (dual work function) or with a common source/drain electrode in the memory region (borderless contact). In the latter case, all the transistors of the semiconductor circuit receive the same gate doping. A method is proposed by which it is possible to realize dual work function and borderless contact on a semiconductor substrate simultaneously in a simple manner.
233 Citations
18 Claims
-
1. A method for fabricating an integrated semiconductor circuit, which comprises:
-
depositing a first layer sequence onto a semiconductor substrate, the first layer sequence having a bottommost layer composed of an oxidizable material;
patterning the first layer sequence by anisotropic etching in a first area region of the semiconductor substrate to form first gate structures having sidewalls and top sides, surfaces of the semiconductor substrate lying parallel to the top sides being defined between the gate structures, and removing the first layer sequence in a second area region of the semiconductor substrate;
oxidizing the bottommost layer of the first layer sequence at the sidewalls of the first gate structures in the first area region;
covering, in the first area region, at least the top sides of the first gate structures and the surfaces of the semiconductor substrate with an etch stop layer;
covering the first gate structures of the first area region by depositing a second layer sequence onto the semiconductor substrate;
patterning the second layer sequence by anisotropic etching of the second layer sequence to form second gate structures in the second area region and removing the second layer sequence from the first gate structures in the first area region, and stopping the removing of the second layer sequence in the first area region with the etch stop layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
-
Specification