Patent ID: 8865538
Filing Date: 2014-10-21
Classification: C23C,H01L

Abstract:
1. A method of forming a semiconductor device, comprising: providing a substrate defined with a first device region and a second device region and having an interface layer on the first device region and on the second device region, said interface layer comprising an oxide or oxynitride; depositing a first high-k film on the interface layer; performing a heat-treatment to form a modified interface layer by diffusion of a metal element from the first high-k film into the interface layer; depositing a first threshold voltage adjustment layer on the first high-k film, wherein the first threshold voltage adjustment layer contains a first metal element selected from Mg, Ca, Sr, Ba, Sc, Ti, Y, La, V, Nb, Ta, Al, Ga, In, Tl, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, or Lu, or a combination thereof; removing the first threshold voltage adjustment layer from the second device region; following the removing, depositing a second threshold voltage adjustment layer over the first high-k film; thereafter, depositing a second high-k film above the first high-k film; depositing a gate electrode film on the second high-k film; defining a first gate stack in the first device region, the first gate stack containing the modified interface layer, the first high-k film, the first threshold voltage adjustment layer, the second threshold layer, the second high-k film, and the gate electrode film; and defining a second gate stack in the second device region, the second gate stack containing the modified interface layer, the first high-k film, the second threshold layer, the second high-k film, and the gate electrode film, wherein the second threshold voltage adjustment layer abuts the second high-k film and the first threshold voltage adjustment layer in the first device region, and wherein the second threshold voltage adjustment layer abuts the second high-k film and the first high-k film in the second device region.