Ion-channeling and optical absorption studies of implantation disorder in germanium

Ion‐channeling and optical absorption measurements are reported for lattice disorder in Ge after ion implantation at 90 K. An anneal stage is observed by ion channeling at 175 K for low‐fluence Zn implants (3×10¹²/cm²). The annealing occurs over a much narrower temperature range (∼50 K) than is observed for low‐temperature implantation disorder in Si. The Ge anneal stage measured by ion channeling is shown to correlate closely with that observed by near‐band‐edge optical absorption measurements for these low‐disorder‐density implants. For high‐disorder‐density implants (e.g., ${\text{≳3×10}}^{13}\hspace{0.17em}{\mathrm{Zn/cm}}^2$ ) ion‐channeling measurements saturate due to a loss of long‐range order, while near‐edge absorption measurements are still sensitive to further changes in the disorder. Following high‐disorder‐density implants near‐edge absorption shows appreciable recovery below room temperature, while ion channeling shows recovery of the long‐range order at temperatures $\text{≳450\hspace{0.17em}}\mathrm{K}$ . Thus, ion‐channeling and optical absorption measurements of ion‐induced disorder in Ge are shown to correlate for low‐disorder‐density implants and provide complementary information for high‐disorder‐density implants.