High-performance fully depleted silicon-on-insulator transistors

Thin single-crystal silicon-on-insulator films with defect densities as low as 8×10⁵ dislocations/cm² were formed by implantation of 1.5×10¹⁸ O⁺/cm² at 150 kV into bare silicon and annealing at 1350°C for 6 h in nitrogen. Thin-film submicrometer MOS transistors were fabricated with self-aligned TiSi₂ fully covering sources, drains, and gates, and with p⁺ and n⁺ polysilicon gates for PMOS and NMOS transistors, respectively, but without a lightly doped drain. Transistors with gate lengths as short as 0.4 μm exhibited essentially long-channel behavior with no kink and with a high saturation current. The device physics was investigated using PISCES simulations, which agreed well with the experimental results. A ring-oscillator stage delay of 58 ps was obtained for 1.0-μm gate length CMOS circuits operating at 5 V