Papers by Author: Russell Gwilliam

Abstract: Buried gate static induction transistors (BGSITs) were fabricated on commercial 4H-SiC wafer with 20 m thick n-type epilayer having a net donor density of 0.71015 cm-3. Buried gate regions were formed by the selective implantation of high energy (up to 2 MeV) aluminium performed at 600 °C. Nitrogen was implanted at temperature of 400 °C to form a heavily doped blanket source region. Post-implantation annealing was carried out at the atmospheric pressure in argon using a graphite capping layer. Fabricated normally-on devices with source contact diameter of 0.2 mm were tested at temperatures up to 500 °C and current densities up to 270 A/cm2. The specific on-resistance of a completely open 4H-SiC BGSIT was 34 mcm2 and showed a thermally activated behaviour at temperatures up to 500 °C.

Abstract: This paper reviews the physics and the potential application of ion-implanted vacancies for high-performance B-doped ultra-shallow junctions. By treatment of silicon films with vacancygenerating implants prior to boron implantation, electrically active boron concentrations approaching 1021 cm-3 can be achieved by Rapid Thermal Annealing at low temperatures, without the use of preamorphisation. Source/drain (S/D) junctions formed by advanced vacancy engineering implants (VEI) are activated far above solubility. Furthermore, in the case of appropriately engineered thin silicon films, this activation is stable with respect to deactivation and the doping profile is practically diffusionless. Sheet resistance Rs is predicted to stay almost constant with decreasing junction depth Xj, thus potentially outperforming other S/D engineering approaches at the ‘32 nm node’ and beyond.