Mixed crystal orientation strain silicon substrate and method for preparing same

Abstract

The invention provides a mixed crystal orientation strain silicon substrate, which comprises a support substrate, a germanium-silicon layer directly arranged on the surface of the support substrate and a strain silicon layer directly arranged on the surface of the germanium-silicon layer. The invention further provides a method for preparing the mixed crystal orientation strain silicon substrate.The mixed crystal orientation strain silicon substrate has the advantages of lowering dislocation density of the first germanium-silicon layer, ensuring the strain state of a first strain area, and improving quality of crystal lattice and strain degree of the strain silicon layer when used in the mixed crystal orientation strain silicon substrate as a buffer layer between the support substrate and the strain silicon layer. The preparation method has the advantages of not needing processes of polishing, epitaxy, linkage and the like after the strain silicon layer is fully developed and ensuring the strain degree of the strain silicon.

Description

【Technical field】 [0001] The invention relates to the field of semiconductor manufacturing, in particular to a mixed crystal orientation strained silicon substrate and a preparation method thereof. 【Background technique】 [0002] In the current semiconductor technology, CMOS circuits are mainly fabricated on silicon substrates with (100) crystal planes, because of the small oxide-interface charge density and the highest electron mobility on the (100) crystal planes . However, the mobility of holes is only about 1 / 4-1 / 2 of the corresponding electron mobility on (100) wafers, which makes the drive current of pMOSFETs prepared on (100) wafers about half that of nMOSFETs, While traditionally larger pMOSFETs can be used to balance nMOSFETs, in practice this increases gate and parasitic capacitance. It has been reported that the performance of pFETs can be improved by shifting the channel orientation from <110> to <100> on (100) substrates, but more work has focused ...

AI Technical Summary

Problems solved by technology

[0004] The problem of the prior art is that the substrate with mixed crystal orientation has two or more different crystal orientations on the same substrate, and the dislocation density generated due to the stress mismatch of the crystal lattice is high, which cannot meet the requirements of Device application

Images