| Summary: | 碩士 === 國立臺灣科技大學 === 機械工程系 === 90 === For high speed PIN Photo Diode, there were two subjects in this study. In first subject, various process parameters and new structures have been used to improve the response time of photo diodes. To estimate the response time of photo diodes was done by Tr/Tf measurement and by RC time constant. In second subject, the gold film which deposited on the device with/without Alloying(390℃,30min) were investigated.
The results are as follow: In first subject, Devices without opaque Al overlayer, which have longer saturation time, could not improve the response time further. The optimum process parameter is Si (111) diffusion wafer which has a structure of 40μm high resistance layer and doping by “Boron plus wafer”, capping opaque Al overlayer. In second subject, before Alloying the interdiffusion of Si atom was very clear. The Si atom was contained stablely in about 30 at% in the Au overlayer, but the Au atom was not found in the Si substrate. After Alloying the surface of gold film had changed from continued surface to island grain. There were many Si clusters which have the same diamond structure and orientation relationship with Si substrate in Au overlayer. The concentration of Si atom was about 30 at% in the Au overlayer, and the Au atom was 0 at% in Si substrate.
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