0.18 μm metal gate fully-depleted SOI MOSFETs for advanced CMOS applications

Abstract

We report here for the first time a 0.18ym fully-depleted SO1 process with PVD TiN metal gate. Because midgap work function metal gate and very light channel doping were used, threshold voltage can he easily controlled in +300mV to +5OOmV range and on-wafer Vt variation was only about Results and Discussions +5mV. Short channel effects can be further improved when a) Vt and Subthreshold Slope silicon film thickness is thinner than 300A. Subthreshold Vts can be easily controlled in the +300mV to +500mV slope was kept helow 75mV/dec even for subnominal devices range by using midgap work function metal gate and very and Vt roll-offs for both N-and P-MOSFETs were very small. light channel doping. PMOSFETs Vt roll-off is still quite serious when Tsi (thickness of silicon) is at 500A range Introduction (Fig.2), hut this can he much improved by thinning Tsi to FD (Fully-Depleted) SO1 is very attractive for deep sub-about 270A (Fig.3). Subthreshold slope under 75mV/dec can quarter micron CMOS applications hecause of its quasi-ideal he achieved in this manner (Fig.4). properties, easier isolation and simpler front-end process [I].

FDSOI Process Technology for Subthreshold-Operation Ultra-Low-Power Electronics

“…There are several literature examples of successful integration of mid-gap metal gate transistors, including SiGe, Ta , and TiN. (12)(13)(14)(15)(16)(17) A metal gate stack typically consists of a thin metal layer sandwiched between a thicker polysilicon layer above, and the gate dielectric below. The gate dielectric may be a conventional SiO 2 or SiON gate oxide, or a high-k gate dielectric such as HfSiON.…”

FDSOI Process Technology for Subthreshold-Operation Ultralow-Power Electronics

“…Therefore, a workfunction-engineered mid-gap metal gate material [10], [16], [17] should be used to provide symmetric threshold voltages for NMOS and PMOS. There are several literature examples of successful integration of mid-gap metal gate transistors, including SiGe [15], Ta [10], [18], and TiN [19]- [26].…”

Work function tuning of the TixTayN metal gate electrode for advanced metal-oxide-semiconductor devices applications

“…2 Therefore, the combination of the advantages of the metal gate with the high-dielectric-constant ͑high-k͒ gate dielectric would be an attractive technology option for the advanced MOS devices applications. 1 However, the MOS devices with the conventional dual-poly gate electrodes are not suitable for the advanced memory and logic applications.…”