New planar self-aligned double-gate fully-depleted P-MOSFETs using epitaxial lateral overgrowth (ELO) and selectively grown source/drain (S/D)

Simulations have shown that self-aligned double-gate SOI MOSFETs are able to eliminate short channel effects and increase circuit performance for devices down to the L~20-30 nm regime (Frank et al., 1992; Wong et al., 1994 and 1998; Fossum et al., 1998). Planar self-aligned fully-depleted double-gate structures are considered most promising (Wong et al., 1997). However, previous proposed fabrication processes have not shown experimental data with low subthreshold slopes or off-currents (Lee et al., 1999). This work presents, for the first time, successfully fabricated planar self-aligned double-gate P-MOSFETs with a good subthreshold swing (<70 mV/dec) and low leakage current (I_off<0.3 pA/μm) using epitaxial lateral overgrowth (ELO). It also has a unique selective epitaxially grown source/drain (S/D). The measured hole mobility, 215 cm²/V-s at V_GS -V_T=-0.6 V, shows the good channel and interface quality obtained by using ELO