Strained silicon PMOS having silicon germanium source/drain extensions and method for its fabrication
AssigneeAdvanced Micro Devices, Inc.
InventorsQi Xiang, Eric N. Paton, Haihong Wang
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Abstract
A strained silicon p-type MOSFET utilizes a strained silicon channel region formed on a silicon germanium substrate. Silicon germanium regions are formed on the silicon germanium layer adjacent to ends of the strained silicon channel region, and shallow source and drain extensions are implanted in the silicon germanium material. The shallow source and drain extensions do not extend into the strained silicon channel region. By forming the source and drain extensions in silicon germanium material rather than in silicon, source and drain extension distortions caused by the enhanced diffusion rate of boron in silicon are avoided.
Claims19
A method for forming a p-type metal oxide semiconductor field effect transistor (MOSFET), comprising:
- providing a substrate comprising a layer of silicon germanium having a layer of strained silicon formed thereon, and having a gate insulator formed on the strained silicon layer and a gate formed on the gate insulator;
- forming a first spacer around the gate and gate insulator;
- removing the strained silicon layer from source and drain regions to form trenches that expose the silicon germanium layer in the source and drain regions and to form a strained silicon channel region beneath the gate insulator;
- growing silicon germanium regions on the silicon germanium layer to fill the trenches;
- and
- implanting shallow source and drain extensions in silicon germanium material adjacent to ends of the channel region, wherein the shallow source and drain extensions do not extend into to the strained silicon channel region after being implanted.
Dependencies are inferred from the claim text.