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 × 10
²⁰
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 (PO
_x
/SiO
_y
and Sb
₂
O
₅
) films were uniformly deposited. Using the conventional RTP method led to a low doping concentration (<;3 × 10
¹⁹
cm
^-3
). However, FLP with a Xenon (Xe) lamp (lamp duration: 3 ms; energy density: 56 J/cm
²
) raised the surface temperature to nearly 800 °C. Furthermore, high concentrations of both P and Sb (>1 × 10
²⁰
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.