Strained Si/SiGe MOS technology: Improving gate dielectric integrity

• Published in: Microelectronic engineering Vol. 86; no. 3; pp. 218 - 223
• Main Authors: Olsen, S.H., Yan, L., Agaiby, R., Escobedo-Cousin, E., O’Neill, A.G., Hellström, P.-E., Östling, M., Lyutovich, K., Kasper, E., Claeys, C., Parker, E.H.C.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.03.2009; Elsevier
• Subjects: alloys; Applied sciences; buffers; Dielectric; diffusion; Electrical engineering, electronics and photonics; electrical-properties; Electronics; Elektroteknik, elektronik och fotonik; Exact sciences and technology; Gate leakage; layers; Lifetime; Mobility enhancement; Molecular electronics, nanoelectronics; MOSFET; n-mosfets; reliability; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; si1-xgex; SiGe; TECHNOLOGY; TEKNIKVETENSKAP; Transistors; Virtual substrate; Performance evaluation; MOS technology; Semiconductor alloys; MOSFET; Dielectric reliability; Thermal behavior; Roughness; Short channel; Transistor gate; Durability; Nanoelectronics; Lifetime; Misfit dislocation; Mobility enhancement; SiGe; Gate oxide; Si; Self heating; Thermal conductivity; Leakage current; Gate leakage; Reliability; Gain; Virtual substrate
• ISSN: 0167-9317; 1873-5568; 1873-5568
• DOI: 10.1016/j.mee.2008.08.001

Strained Si is recognised as a necessary technology booster for the nanoelectronics regime. This work shows that high levels of stress attainable from globally strained Si/SiGe platforms can benefit gate leakage and reliability in addition to MOSFET channel mobility. Device self-heating due to the low thermal conductivity of SiGe is shown to be the dominating factor behind compromised performance gains in short channel strained Si/SiGe MOSFETs. Novel thin virtual substrates aimed at reducing self-heating effects are investigated. In addition to reducing self-heating effects, the thin virtual substrates provide further improvements to gate oxide integrity, reliability and lifetime compared with conventional thick virtual substrates. This is attributed to the lower surface roughness of the thin virtual substrates which arises due to the reduced interactions of strain-relieving misfit dislocations during thin virtual substrate growth. Good agreement between experimental data and physical models is demonstrated, enabling gate leakage mechanisms to be identified. The advantages and challenges of using globally strained Si/SiGe to advance MOS technology are discussed.