Electron mobility enhancement in strained-Si n-MOSFETs fabricated on SiGe-on-insulator (SGOI) substrates

We demonstrate electron mobility enhancement in strained-Si n-MOSFETs fabricated on relaxed Si/sub 1-x/Ge/sub x/-on-insulator (SGOI) substrates with a high Ge content of 25%. The substrates were fabricated by wafer bonding and etch-back utilizing a 20% Ge layer as an etch stop. Epitaxial regrowth was used to produce the upper portion of the Si/sub 0.75/Ge/sub 0.26/ and the surface strained Si layer. Large-area strained-Si n-MOSFETs were fabricated on this SGOI substrate. The measured electron mobility shows significant enhancement over both the universal mobility and that of co-processed bulk-Si MOSFETs. This SGOI process has a low thermal budget and thus is compatible with a wide range of Ge contents in Si/sub 1-x/Ge/sub x/ layer.