Method for manufacturing semiconductor device

Abstract

A method of fabricating a semiconductor device for improving the performance of "Sigma" shaped embedded source / drain regions is disclosed. A "U" shaped recess is formed in a Si substrate. The recess is treated with a surfactant, the amount of surfactant adsorbed on the recess sidewalls being greater than that on the recess bottom. An oxide is formed on the bottom. The presence of surfactant on the sidewalls, prevents oxide from forming thereon. The surfactant on the sidewalls is then removed and an orientation selective wet etching process is performed on the sidewalls. The oxide protects the Si at the bottom is from being etched.

Description

technical field [0001] The invention relates to a manufacturing method of a semiconductor device, in particular to a manufacturing method of a semiconductor device with a "Σ"-shaped embedded source and drain region. Background technique [0002] The development of semiconductor technology follows Moore's Law, and the critical dimensions are getting smaller and smaller. A technique of embedding silicon germanium (SiGe) in recessed source / drain regions to enhance channel mobility of PMOS devices has been proposed. Since the lattice constant of SiGe is larger than that of Si, it can provide compressive stress between the source and drain regions in the channel region of the PMOS device, thereby enhancing the hole mobility of the PMOS device. [0003] In order to enhance the effect of applying stress, a technical scheme of forming a "Σ"-shaped groove and filling it with SiGe is further proposed. [0004] figure 1 A "Σ" shaped groove formed in the substrate is schematically sh...

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Problems solved by technology

[0008] However, since the etching rate in the crystal direction and the crystal direction is larger than that in the crystal direction, it often causes the flat bottom 260 of the groove 215 to be etched as Figure 2B pointed

However, if SiGe is epitaxially grown on the pointed bottom of groove 215, high-quality SiGe cannot be obtained.

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