Semiconductor device with strained transistors and its manufacture

A method of manufacturing a semiconductor device comprising:n(1) forming a first gate electrode above an n-channel field effect transistor region of a semiconductor substrate made of a first semiconductor material, and forming a second gate electrode above a p-channel field effect transistor region of the semiconductor substrate made of the first semiconductor material;(2) forming a first insulating mask layer over the semiconductor substrate, covering the first gate electrode and the second gate electrode;(3) forming a resist mask covering the p-channel field effect transistor region and exposing the n-channel field effect transistor region, anisotropically etching the first insulating mask layer in the n-channel field effect transistor region to leave the first insulating mask layer as first sidewall spacers on sidewalls of the first gate electrode;(4) etching the semiconductor substrate in the n-channel field effect transistor region by using the first insulating mask layer, the first sidewall spacers and the first gate electrode as an etching mask, to form first recesses;(5) epitaxially growing source/drain regions of a second semiconductor material different from the first semiconductor material, in the first recesses;(6) after epitaxially growing source/drain regions of the second semiconductor material, removing the first insulating mask layer and the first sidewall spacers;(7) after removing the first insulating mask layer and the first sidewall spacers, forming second sidewall spacers of an insulating material on sidewalls of the first gate electrode and the second gate electrode;(8) after forming the second sidewall spacers, forming a second insulating mask layer covering the n-channel field effect transistor region;(9) etching the semiconductor substrate in the p-channel field effect transistor region by using the second insulating mask layer, the second sidewall spacers, and the second gate electrode, as an etching mask, to form second recesses; and(10) epitaxially growing source/drain regions of a third semiconductor material different from the first semiconductor material, in the second recesses.