Keywords: supersaturated doping; positron annihilation technique; pulsed laser; infrared enhanced absorption
In this paper, supersaturated sulfur-doped silicon materials were prepared by pulsed laser gas phase doping and ion implantation respectively. The doped samples were annealed by conventional hot furnace and excimer laser. The pulsed laser flux, wavelength and scanning were studied. The effects of rate, ion implantation conditions and annealing process on the surface morphology, light absorption, carrier concentration and mobility of the sample. The microstructure information such as surface morphology, crystal structure and defects of the sample was characterized by scanning electron microscopy, Raman spectroscopy and positron annihilation. The experimental results show that the surface morphology of the sample enhances the absorption rate in the visible range of the material, which is mainly due to the high absorption of visible light on the surface of the sample through multiple reflections. Compared with the conventional furnace annealing, the pulsed laser annealed sample The decrease of the light absorption rate in the infrared wavelength range is caused by the precipitation of part of the sulfur impurities in the doped sample after annealing in the conventional hot furnace, which indicates that the supersaturated sulfur impurity in the silicon has the infrared enhanced absorption property of the system. Important role; Doppler broadening spectrum indicates that the photoelectric properties of the system are closely related to the microstructure of the annealing process, surface morphology and defects. On this basis, the detector with room temperature low bias and high gain performance was developed by using the prepared materials, and the gain mechanism and infrared response characteristics were discussed.