Germanium n+/p Shallow Junction With Record Rectification Ratio Formed by Low-Temperature Preannealing and Excimer Laser Annealing

Abstract

A germanium n + /p shallow junction formed by a combination of low-temperature preannealing (LTPA) and excimer laser annealing at a low fluence of 150 mJ/cm 2 for phosphorus-implanted germanium is demonstrated. The LTPA step plays a critical role in annihilating the implantation damages and significantly suppressing phosphorus diffusion during laser annealing process, resulting in a very small dopant diffusion length with high activation level of phosphorus. A well-behaved Ge n + /p shallow junction diode with a record rectification ratio of ~10 7 and low leakage current density of 8.3 × 10 -5 A/cm 2 is achieved, which is greatly beneficial to the scaled Ge MOSFET technology.