Control of Self-Heating in Thin Virtual Substrate Strained Si MOSFETs

• Published in: IEEE transactions on electron devices Vol. 53; no. 9; pp. 2296 - 2305
• Main Authors: Olsen, S.H., Escobedo-Cousin, E., Varzgar, J.B., Agaiby, R., Seger, J., Dobrosz, P., Chattopadhyay, S., Bull, S.J., O'Neill, A.G., Hellstrom, P.-E., Edholm, J., Ostling, M., Lyutovich, K.L., Oehme, M., Kasper, E.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01-09-2006; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: alloys; Applied sciences; buffer layers; Devices; Electronics; Exact sciences and technology; fabrication; field-effect transistors; Germanium; high ge content; mobility; MOSFETs; n-channel mosfets; Oxides; Performance enhancement; quality; relaxation; self-heating; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Silicon; Silicon germanides; silicon germanium; Silicon substrates; strained silicon; Transistors; virtual substrate; Performance evaluation; Semiconductor alloys; High performance; MOSFET; virtual substrate; Thermal behavior; Transistor gate; silicon germanium; Gate oxide; Strained layer; n type semiconductor; strained silicon; Self control; Self heating; Parasitic resistance; self-heating; Series resistance; Wafer; Electrical characteristic; Index Terms-MOSFETs
• ISSN: 0018-9383; 1557-9646; 1557-9646
• DOI: 10.1109/TED.2006.881049

This paper presents the first results and analysis of strained Si n-channel MOSFETs fabricated on thin SiGe virtual substrates. Significant improvements in electrical performance are demonstrated compared with Si control devices. The impact of SiGe device self-heating is compared for strained Si MOSFETs fabricated on thin and thick virtual substrates. This paper demonstrates that by using high-quality thin virtual substrates, the compromised performance enhancements commonly observed in short-gate-length MOSFETs and high-bias conditions due to self-heating in conventional thick virtual substrate devices are eradicated. The devices were fabricated with a 2.8-nm gate oxide and included NiSi to reduce the parasitic series resistance. The strained layers grown on the novel substrates comprising 20% Ge did not relax during fabrication. Good on-state performance, off-state performance, and cross-wafer uniformity are demonstrated. The results show that thin virtual substrates have the potential to circumvent the major issues associated with conventional virtual substrate technology. A promising solution for realizing high-performance strained Si devices suitable for a wide range of applications is thus presented