Method of making transistor with strained source/drain

A method of fabricating a transistor comprises the steps of: forming a gate electrode above a substrate made of a first semiconductor material having a first lattice spacing, forming recesses in the semiconductor substrate at respective locations where a source region and a drain region are to be formed, epitaxially growing a second semiconductor material having a second lattice spacing different from the first lattice spacing in the recesses, and implanting a dopant in the second semiconductor material after the growing step.