Study Of The Process About InGaAs/InP Avalanche Photodiodes

With the in-depth study of infrared radiation and infrared detector, infrared detectors are widely used in temperature measuring radiation, remote sensing, infrared imaging, infrared guidance etc..It was played an important role in the fields of military, medicine, biology, geology and so on. Avalanche photodiode(APD), as a infrared detector with the internal gain, it has the higher gain, faster response speed than traditional PIN infrared detector. So, the APD device in the field of high-speed imaging and optical communication has a better prospects for development. However, avalanche photodiode operates at a high reverse bias voltage, and the performance of dark current, noise, and breakdown is more prominent in APD devices. This also puts forward higher requirements for the preparation process of APD devices.In this paper, the InGaAs/InP avalanche photodiode is studied, and the device has separated structure of absorption,grading,charge and multiplication.This kind of APD was called SAGCM APD for short. In this paper, the device structure and process optimization of SAGCM are carried out, and the fabrication process of the device is finished by the technology of photolithography, etching, passivationand so on. After that, the I-V characteristics and the measurement of the black body detection rate of APD devices have been measured. The main activities include:1. The development status and application prospects of the infrared detectors which included InGaAs/InP avalanche photodiode were introduced.It described the working conditions and structure evolution of APD, and also introduced the main performance parameters of the photoelectric detector.2. Optimized the structure of the original SAGCM, simulated the influence about thickness and doping of absorption layer/the charge layer/the multiplication layer to the electric field distribution of the device, and finally determined the structure parameters of SAGCM-APD.3. Designed the mask layouts for APD, and optimized the shape of the tables and electrodes. This masks also can use for two bands infrared detector.4. The process for APD device is introduced, and the conditions of the technology of lithography, etching, passivation, sputtering electrode and so on are explained. The process was optimized, and compared "dry-wet-dry" etching and dry ICP etching was, and the ICP etching conditions were optimized. The technological feasibility of the passive film was analyzed, and the technological conditions were determined.5. Test electro-optical properties like I-V characteristics and blackbody test.