Patent ID: 8440520
Filing Date: 2013-05-14
Classification: H01L

Abstract:
1. A method of forming a semiconductor device, comprising: providing a substrate defined with a NMOS device region and a PMOS device region, and an interface layer on the NMOS device region and the PMOS device region, depositing a high dielectric constant (high-k) film on the interface layer; depositing a first cap layer on the high-k film, wherein the first cap layer contains a first chemical element for modifying the high-k film in the NMOS device region; removing the first cap layer from the high-k film in the PMOS device region; depositing a second cap layer on the first cap layer in the NMOS device region and on the high-k film in the PMOS device region, wherein the second cap layer contains a second chemical element for scavenging oxygen from the interface layer; performing a heat-treating process to diffuse the first chemical element into the high-k film in the NMOS device region, and to reduce or eliminate the interface layer by oxygen diffusion from the interface layer through the high-k film into the second cap layer; removing the first cap layer and the second cap layer from the high-k film; and depositing a gate electrode film over the high-k film.