High performance 50 nm PMOSFET using decaborane (B10H14) ion implantation and 2-step activation annealing process

A high performance 50 nm PMOSFET with 7-nm-deep ultra shallow junction is described. Ultra-low energy implantation of B₁₀H₁₄ ⁺ at 2 keV (effective energy of boron is 0.2 keV) which never causes transient enhanced diffusion (TED) is utilized for the extension formation. To prevent thermal diffusion (TD), we developed a 2-step activation annealing process (2-step AAP) which forms a shallow extension with a low temperature annealing after the deep source/drain (S/D) formation. The highest drive current of 0.40 mA/um ( I_off of 1 nA/um and V_d = -1.8 V) which improves 15% as compared with published data is achieved. The smallest PMOSFET with a L_eff of 38 nm is demonstrated for the first time. A low S/D series resistance R_sd of 760 ohm-urn is achieved even if using a high sheet resistance (>20 Kohm/sq) for the extension regions due to the diminished extension length.