Ultra-shallow junction and high-k dielectric for Nano CMOS

Abstract

In this work, combination of the plasma doping method with flush lamp annealing (FLA) or solid-state laser annealing (ASLA) is shown to be very promising technique to form ultra-shallow and low-resistive junctions for future nano CMOS. Amorphisation by He plasma (He-PA process) is shown to be effective for obtaining shallow junction depth (Xj) and low sheet resistance (Rs). The He-PA process is found to contribute to the increase of sheet charier concentration, which governs the sheet resistances as revealed by Hall measurements. However, even if these techniques are used, activation rate under the annealing conditions to keep shallow Xj is still low, thus, further investigation to improve the carrier activation is necessary. The junction leakage for the ultra-shallow Si P/N junction diodes formed by plasma doping of boron is examined, and it was shown to be as low as that formed by the low energy ion implantation. Feasibility study of La2O3 gate oxide of MOS capacitors and MOSFET is presented. The effect of annealing temperature on the effective mobility is investigated been obtained and shows strong correlation of the mobility and interface states. Insertion of Y2O3 or Sc2O3 at La2O3/Si interface suppresses the increase of EOT after the annealing.