study of indium super-steep-retrograde for deep submicron nMOSFET

• Main Authors: Yao-jen Lee, 李耀仁
• Other Authors: S.M.Sze
• Format: Others
• Language: en_US
• Published: 2000
• Online Access: http://ndltd.ncl.edu.tw/handle/35391088831036062709

碩士 === 國立交通大學 === 電子工程系 === 88 === The effects of indium implant energy on short-channel effect (SCE) and narrow-channel effect (NCE) were studied on NMOS devices down to 80 nm channel length. An anomalous crossover in threshold voltage roll-off curves was observed, for the first time, on indium-implanted splits with different implant energies. This finding together with the observed reduction in reverse narrow-channel effect (RNCE) with reduced indium implant energy, can be explained by the suppression of transient enhanced diffusion (TED) due to indium deactivation. We have also demonstrated for the first time a high-performance and high-reliability 80 nm-gate-length dynamic threshold voltage MOSFET (DTMOS). Due to indium super steep retrograde In-SSR dopant profile in the channel depletion region, the novel In (150-keV)-doped-split DTMOS features a low threshold voltage and a large body effect to fully exploit the DTMOS advantage. These results are not possible with conventional DTMOS. Excellent transistor characteristics with drive current as high as 348 mA/mm, a record-high Gm of 1,022 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, we have found for the first time that hot-carrier reliability is also improved in DTMOS-mode operation, especially for In (150-keV)-doped-split DTMOS.