Laser thermal annealing of Ge, optimized for highly activated dopants and diode ION/IOFF ratios

The authors compared the influence of laser thermal annealing (LTA) and rapid thermal annealing (RTA) on dopant activation and electrical performance of phosphorus and arsenic doped n+/p junction. High carrier concentration above 10
²⁰
cm
⁻³
as well as an I
ON
/I
OFF
ratio of approximately 10
⁵
and ideality factor (n) approximately 1.2–1.5 was achieved with LTA. However RTA revealed very high I
ON
/I
OFF
ratio approximately 10
⁷
, and n close to 1. Non ideal behavior in LTA diodes is attributed to existence of deep level defects in the junction, contributing to leakage current. Meanwhile ideal behavior of RTA diodes is due to removal of defects in the junction during the high thermal budget.