Process to improve transistor drive current through the use of strain

Abstract

The present invention provides, in one embodiment, a P-type Metal Oxide Semiconductor (PMOS) device ( 100 ). The device ( 100 ) comprises a tensile-strained silicon layer ( 105 ) located on a silicon-germanium substrate ( 110 ) and silicon-germanium source/drain structures ( 135, 140 ) located on or in the tensile-strained silicon layer ( 105 ). The PMOS device ( 100 ) further includes a channel region ( 130 ) located between the silicon-germanium source/drain structures ( 135, 140 ) and within the tensile-strained silicon layer ( 105 ). The channel region ( 130 ) has a compressive stress ( 145 ) in a direction parallel to an intended current flow ( 125 ) through the channel region ( 130 ) Other embodiments of the present invention include a method of manufacturing the PMOS device ( 200 ) and a MOS device ( 300 ).

What is claimed is: 
     
         1 . A method of manufacturing Complementary Metal Oxide Semiconductor (CMOS) integrated circuit include a P-type Metal Oxide Semiconductor (PMOS) device and an N-type Metal Oxide Semiconductor (NMOS) device, comprising:
 epitaxially growing a tensile-strained silicon layer on a silicon-germanium substrate;   removing portions of the tensile-strained silicon layer and also removing a volume of material that was part of the underlying silicon germanium substrate that is outside of a channel region within the PMOS device of the CMOS, but not removing a volume of material that was part of the underlying silicon germanium substrate that is outside of a channel region within the NMOS device of the CMOS; and   epitaxially growing silicon-germanium source/drain structures on or in the tensile-strained silicon layer including the volume that was removed of the silicon germanium substrate.   
     
     
         2 . The method as recited in claim  35 , wherein the tensile-strained silicon layer before the removal of the volume has a thickness between 10 and about 20 nanometers. 
     
     
         3 . The method as recited in claim  35 , wherein removing includes removing between one to ten nanometer thickness of the tensile-strained silicon layer. 
     
     
         4 . The method as recited in claim  35 , wherein epitaxially growing the germanium source/drain structures includes depositing a mixture of silicon and germanium atoms, the mixture having between 30 atom percent and 50 atom percent germanium. 
     
     
         5 . The method as recited in claim  39 , further comprising epitaxially growing silicon-germanium source/drain structures to be free of physical contact with the silicon-germanium substrate.