METHOD AND STRUCTURE FOR LOW RESISTIVE SOURCE AND DRAIN REGIONS IN A REPLACEMENT METAL GATE PROCESS FLOW

摘要

In one embodiment a method is provided that includes providing a structure including a semiconductor substrate (12) having at least one device region (14) located therein, and a doped semiconductor layer located on an upper surface of the semiconductor substrate in the at least one device region. After providing the structure, a sacrificial gate region (28) having a spacer (34) located on sidewalls thereof is formed on an upper surface of the doped semiconductor layer. A planarizing dielectric material (36) is then formed and the sacrificial gate region (28) is removed to form an opening (38) that exposes a portion of the doped semiconductor layer. The opening is extended to an upper surface of the semiconductor substrate (20) and then an anneal is performed that causes outdiffusion of dopant from remaining portions of the doped semiconductor layer forming a source region (40) and a drain region (42) in portions of the semiconductor substrate that are located beneath the remaining portions of the doped semiconductor layer. A high k gate dielectric (46) and a metal gate (48) are then formed into the extended opening.