Boosting n-type doping levels of Ge with co-doping by integrating plasma-assisted atomic layer deposition and flash annealing process

To achieve a high concentration of dopants over 1 × 1020 cm-3 on germanium (Ge), co-doping with phosphorus (P) and antimony (Sb) by plasma assisted atomic layer deposition (PALD) and a subsequent annealing process [rapid thermal annealing process (RTP) or flash lamp annealing process (FLP)] are proposed and investigated. We found that the PALD stacked co-doping (POx /SiOy and Sb2O5 ) films were uniformly deposited. Using the conventional RTP method led to a low doping concentration (19 cm-3 ). However, FLP with a Xenon (Xe) lamp (lamp duration: 3 ms; energy density: 56 J/cm2 ) raised the surface temperature to nearly 800 °C. Furthermore, high concentrations of both P and Sb (>1 × 1020 cm-3 ) were achieved at the surface. Our findings suggest that the FLP with high energy in a short amount of time (~3 ms) can create the peak power effect and the co-doping effect. The evidence shows that these effects contribute to enhancing n-type doping levels in the Ge structure