锗近红外光电探测器制备工艺研究进展

Ge材料由于在近红外波段具有较大的吸收系数、高的载流子迁移率、以及与Si工艺相兼容等优势而被视为制备近红外光电探测器最理想的材料之一。针对Ge光电探测器制备过程中面临的挑战，文中综述了近年来笔者所在的课题组在Ge探测器材料、器件及工艺方面的研究进展。首先介绍了Si基Ge材料的制备工艺，利用低温缓冲层生长技术、Ge/Si键合技术、Ge浓缩技术等分别制备得到高晶体质量的Si基Ge材料。研究了Ge材料n型掺杂工艺，利用离子注入结合两步退火处理（低温预退火和激光退火）以及利用固态磷旋涂工艺等分别实现Ge材料n型高掺浅结制备。最后探究了金属/Ge接触势垒高度的调制方法，结合金属中间层和透明导电电极ITO制备得到性能良好的Ge肖特基光电探测器。

Research progress of technologies for germanium near-infrared photodetectors

Germanium (Ge) is considered as one of the most promising materials for near infrared (NIR) photodetectors, due to its large absorption coefficient at NIR wavelengths, high carrier mobilities, and process compatibility with silicon (Si) architecture. Focusing on the challenges of Ge NIR photodetectors, in this paper, the progress of Ge materials and technologies for photodetectors in our group was reviewed extensively. Firstly, the preparation process of Si-based Ge materials was introduced, in which high crystal quality Si-based Ge materials were fabricated by a two-step epitaxy method, Ge/Si wafer bonding, and Ge condensation techniques, respectively. Then the n-type doping technology of Ge was studied, in which high n-type doping concentrations and shallow junctions of Ge materials were prepared by two-step annealing (low temperature pre-annealing and excimer laser annealing) for phosphorus-implanted Ge substrate and spin-on doping of phosphorus on Ge substrate, respectively. Finally, the modulation of Schottky barrier height of metal/Ge contacts were studied, and a high-performance Ge Schottky photodetector was prepared by combining ITO transparent electrode and ultra-thin metal film interlayer.