Ultrathin strained-SOI by stress balance on compliant substrates and FET performance

• Published in: IEEE transactions on electron devices Vol. 52; no. 10; pp. 2207 - 2214
• Main Authors: Haizhou Yin, Hobart, K.D., Peterson, R.L., Kub, F.J., Sturm, J.C.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.10.2005; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Annealing; Applied sciences; Boron compounds; Compliant substrate; Devices; Diffusion barriers; Dislocations; Electronics; Exact sciences and technology; Germanium alloys; Glass; High-temperature techniques; Microelectronic fabrication (materials and surfaces technology); MOSFETs; Phosphorus compounds; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Semiconductor growth; Semiconductor materials; SiGe; Silicon; Silicon alloys; Silicon films; Silicon germanides; Silicon on insulator technology; silicon-on-insulator (SOI); Strain; strained-Si; Stress; Stresses; Transistors; Wafer bonding; Ultrathin films; Performance evaluation; strained-Si; Semiconductor alloys; MOSFET; Annealing; Doped materials; n channel; Stress strain; silicon-on-insulator (SOI); Thin film; Dislocation; Wafer bonding; Silicon on insulator technology; Field effect transistor; Tensile stress; Microelectronic fabrication; Compliant substrate; SiGe; Flexible structure; Strained layer; Diffusion barrier
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/TED.2005.856185

Ultrathin, strained-silicon-on-insulator (s-SOI) structures without a residual silicon-germanium (SiGe) underlayer have been fabricated using stress balance of bi-layer structures on compliant borophosphorosilicate glass (BPSG). The bi-layer structure consisted of SiGe and silicon films, which were initially pseudomorphically grown on a silicon substrate and then transferred onto BPSG by a wafer bonding and SmartCut process. The viscous flow of the BPSG during a high-temperature anneal then allowed the SiGe/Si bi-layer to laterally coherently expand to reach stress balance, creating tensile strain in the silicon film. No dislocations are required for the process, making it a promising approach for achieving high-quality strained-silicon for device applications. To prevent the diffusion of boron and phosphorus into the silicon from the BPSG, a thin nitride film was inserted between the bi-layer and BPSG to act as a diffusion barrier, so that a lightly doped, sub-10-nm s-SOI layer (0.73% strain) was demonstrated. N-channel MOSFETs fabricated in a 25-nm silicon layer with 0.6% strain showed a mobility enhancement of 50%.