High-performance and high-reliability 80-nm gate-length DTMOS with indium super steep retrograde channel

Abstract

In this paper, we demonstrate for the first time a high-performance and high-reliability 80-nm gate-length dynamic threshold voltage MOSFET (DTMOS) using indium super steep retrograde channel implantation. Due to the steep indium super steep retrograde (In-SSR) dopant profile in the channel depletion region, the novel In-SSR DTMOS features a low V-th in the off-state suitable for low-voltage operation and a large body effect to fully exploit the DTMOS advantage simultaneously, which is not possible with conventional DTMOS, As a result, excellent 80-nm gate length transistor characteristics with drive current as high as 348 muA/mum (off-state current 40 nA/mum), a record-high Gm = 1022 mS/mm, and a subthreshold slope of 74 mV/dec, are achieved at 0.7 V operation. Moreover, the reduced body effects that have seriously undermined conventional DTMOS operation in narrow-width devices are alleviated in the In-SSR DTMOS, due to reduced indium dopant segregation. Finally, it was found for the first time that hot-carrier reliability is also improved in DTMOS-mode operation, especially for In-SSR DTMOS.