Patent ID: 8502325
Filing Date: 2013-08-06
Classification: H01L

Abstract:
1. A metal high dielectric constant (MHK) transistor, comprising: a substrate; a MHK gate structure disposed on the substrate between a source region and a drain region, the MHK gate structure comprising a layer of high dielectric constant material and an overlying layer comprised of a metal, the MHK gate structure further having an overlying layer comprised of silicon, where a lateral extent of the layer of high dielectric constant material is greater than lateral extents of the overlying layer comprised of metal and the overlying layer comprised of silicon, the overlying layer comprised of metal and the overlying layer comprised of silicon forming an upstanding portion of the MBK gate structure; a first sidewall layer comprised of silicon disposed on exposed portions of sidewalls of the MHK gate structure to cover sidewalls of the overlying layer comprised of metal and sidewalls of the overlying layer comprised of silicon, the first sidewall layer also being disposed on and in contact with part of a top surface of the layer of high dielectric constant material; a second sidewall layer disposed on and in contact with exposed portions of the first sidewall layer and disposed on and in contact with part of the top surface of the layer of high dielectric constant material; an offset spacer layer disposed over and physically in contact with exposed portions of the second sidewall layer and exposed portions of the layer of high dielectric constant material; and extensions formed in the substrate that underlie the first and second sidewall layers and that extend under a portion but not all of the upstanding portion of the MHK gate structure, wherein each substrate extension overlaps the upstanding portion of the MHK gate structure by an overlap distance.