Strained-Si-on-Insulator (SSOI) and SiGe-on-Insulator (SGOI): Fabrication Obstacles and Solutions

Gianni Taraschi, Arthur J. Pitera, Lisa M. McGill, Zhi-Yuan Cheng, Minjoo L. Lee, Thomas A. Langdo, Eugene A. Fitzgerald
2002 Materials Research Society Symposium Proceedings  
Advanced CMOS substrates composed of ultra-thin strained-Si and SiGe-on-insulator were fabricated, combining both the benefits of high-mobility strained-Si and SOI. Our pioneering method employed wafer bonding of SiGe virtual substrates (with strained-Si layers) to oxidized handle wafers. Layer transfer onto insulating handle wafers can be accomplished using grindetchback or delamination via implantation. Both methods were found to produce a rough transferred layer, but polishing is
more » ... hing is unacceptable due to non-uniform material removal across the wafer and the lack of precise control over the final layer thickness. To solve these problems, a strained-Si stop layer was incorporated into the bonding structure. After layer transfer, excess SiGe was removed using a selective etch process, stopping on the strained-Si. Within the context of ultra-thin SSOI and SGOI fabrication, this paper describes recent improvements including metastable stop layers, low temperature wafer bonding, and improved selective SiGe removal.
doi:10.1557/proc-745-n4.7 fatcat:ecfed4de45ac3kwok5fww5cul4