Quantifying self-heating effects with scaling in globally strained Si MOSFETs

Abstract

Electrical results are presented for deep submicron strained Si MOSFETs fabricated on both thick and thin SiGe strain relaxed buffers, SRBs. For the first time thin SRB devices are shown to offer the same performance enhancements as thick SRB devices. The reduction in performance enhancement with device scaling widely reported in the literature has also been investigated. Correcting for dynamic self-heating effects using ac measurements, the enhancements seen in long channel devices are maintained down to short channel lengths, demonstrating the scalability of SRB technology. Thermal resistances have been measured experimentally and compared with analytical models. The thermal resistance for devices on the thin SRBs is reduced by 50% compared with devices on thick SRBs. Finally, a comparison of self-heating effects in MOSFETs fabricated on SOI and Si 0.8Ge 0.2 SRBs provides insight into the challenges ahead as power densities continue to increase.