Patent ID: 7598545
Filing Date: 2009-10-06
Classification: H01L

Abstract:
1. A complementary metal oxide semiconductor (CMOS) structure comprising: a semiconductor substrate; at least one nMOS device located on one region of said semiconductor substrate; and at least one pMOS device located on another region of said semiconductor substrate, where said at least one nMOS device includes a gate stack comprising at least a low workfunction elemental metal having a workfunction of less than 4.2 eV and an in-situ metallic capping layer, and said at least one pMOS includes a gate stack comprising at least a high workfunction elemental metal having a workfunction of greater than 4.9 eV and a metallic capping layer, wherein a surface oxide layer is present between the high work function element metal and the metallic capping layer of the at least one pMOS, wherein the surface oxide layer is not present between the low work function element metal and the in-situ metallic capping layer of the nMOS.