Dual work function CMOS devices
A method for forming a semiconductor device includes forming a first channel region and a second channel region on a substrate, depositing a dielectric material layer on the first channel region and the second channel region, and depositing a barrier layer on the dielectric material layer on the first channel region and the second channel region. A metal layer is deposited on the barrier layer on the first channel region and the second channel region. A portion of the metal layer and the barrier layer on the first channel region and a portion of the metal layer on the second channel region are removed to expose the barrier layer on the second channel region. A layer of workfunction material is deposited on an exposed portion of the dielectric material layer on the first channel region and over the barrier layer on the second channel region.
1. A method for forming a semiconductor device, the method comprising:
forming, on an insulator layer, a first channel region with a fin extending vertically upwardly from the insulator layer and a second channel region with a fin extending upwardly from the insulator layer, the fin of the second channel region including a different material than the fin of the first channel region;
depositing a dielectric material layer on the first channel region, the second channel region and a portion of the insulator layer between the fin of the first channel region and the fin of the second channel region;
depositing a barrier layer on the dielectric material layer on the first channel region, the second channel region and the portion of the insulator layer;
depositing a metal layer on the barrier layer on the first channel region, the second channel region and the portion of the insulator layer;
patterning a mask in contact with a portion of the metal layer in the second channel region and a first sub-portion of the portion of the insulator layer proximate to the fin of the second channel region;
removing a portion of the metal layer and the barrier layer on the first channel region and a second sub-portion of the portion of the insulator layer proximate to the fin of the first channel region;
after removing the portion of the metal layer and the barrier layer, removing an entirety of the metal layer on the second channel region and the first sub-portion of the portion of the insulator layer proximate to the fin of the second channel region to expose the barrier layer on the second channel region and the first sub-portion of the portion of the insulator layer proximate to the fin of the second channel region; and
depositing a layer of workfunction material on an exposed portion of the dielectric material layer on the first channel region and the second sub-portion of the portion of the insulator layer proximate to the fin of the first channel region and over the barrier layer on the second channel region and the first sub-portion of the portion of the insulator layer proximate to the fin of the second channel region.
2. The method of claim 1 , wherein the second channel region includes germanium.
3. The method of claim 2 , wherein depositing the layer of workfunction material on the exposed portion of the dielectric material layer on the first channel region and over the barrier layer on the second channel region includes depositing the layer of workfunction material directly on an exposed portion of the dielectric material layer on the first channel region and directly over the barrier layer on the second channel region.