High performance mechanisms of near-infrared photodetectors with microcrystalline SiGe films deposited using laser-assisted plasma enhanced chemical vapor deposition system.

The SiH(4) and GeH(4) reactant gases used for depositing microcrystalline SiGe films could be simultaneously decomposed when acted cooperatively on the plasma and the assistant CO(2) laser in the laser-assisted plasma enhanced chemical vapor deposition system. The carrier mobility of the 80 W laser-assisted SiGe films was significantly increased to 66.8 cm(2)/V-s compared with 2.22 cm(2)/V-s of the non-laser-assisted SiGe films. The performances of the resulting p-Si/i-SiGe/n-Si near-infrared photodetectors were improved due to the high quality and high carrier mobility of the laser-assisted SiGe films. The maximum photoresponsivity and the maximum quantum efficiency of the photodetectors with 80 W laser-assisted SiGe films were respectively improved to 0.47 A/W and 68.5% in comparison with 0.31 A/W and 46.5% of the photodetectors with non-laser-assisted SiGe films.