Silicon-germanium virtual substrate and method of fabricating the same
A method of forming a relaxed silicon-germanium layer for accommodation of an overlying silicon layer formed with tensile strain, has been developed. The method features growth of multiple composite layers on a semiconductor substrate, with each composite layer comprised of an underlying silicon-germanium-carbon layer and of an overlying silicon-germanium layer, followed by the growth of an overlying thicker silicon-germanium layer. A hydrogen anneal procedure performed after growth of the multiple composite layers and of the thicker silicon-germanium layer, results in a top composite layer now comprised with an overlying relaxed silicon-germanium layer, exhibiting a low dislocation density. The presence of silicon-carbon micro crystals in each silicon-germanium-carbon layer reduces the formation of, and the propagation of threading dislocations in overlying silicon-germanium layers, therefore also reducing extension of these defects into an overlying silicon layer, wherein the tensile strained silicon layer will be used to accommodate a subsequent device structure.
Chartered Semiconductor Manufacturing Ltd.
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H01L H01L
inventional inventional
Jin Ping
Liu