本論文中描述於N型(111) 矽基板上調變不同蝕刻參數形成複層孔隙率(multi-porosity)多孔矽基板，利用多孔矽結構來增加光線吸收面積與偏移吸收峰值等特性，發展光感測元件。其中多孔矽層是以電化學陽極化蝕刻法(electrochemical anodization method) 製作而成，於其上再以快速升溫化學氣相沉積系統(RTCVD) 成長單晶碳化矽薄膜。利用碳化矽／多孔矽結構製作的垂直式PN接面二極體其主要吸收層在於多孔矽層，具有0.41A/W之響應度、60.22%之量子效率，常溫6.5mW/cm2螢光燈照射下其光暗電流增益值為393.83，與傳統碳化矽／單晶矽結構相較提升近4倍。此外，碳化矽MSM(metal-semiconductor-metal)結構光感測元件則因多孔矽層的高電阻值絕緣特性，使主要吸收層落在碳化矽薄膜，具有0.20A/W之響應度，量子效率為44.62%。實驗結果驗證成長於複層孔隙率多孔矽基板上的碳化矽／多孔矽元件，具有較佳的光感測特性與靈敏度，因此更適合應用於元件的製作與發展。

In this thesis, we used various etching conditions to develop PS (porous-Si) substrates with multi-porosity. The PS structure can increase photo-absorbing area, and shift the peak of the main absorbing wavelength, thus improving the flexibility for designing a photo-detecting device. The PS layers were formed on the silicon substrates pre-etched using the electrochemical anodization method. Then deposited theβ-SiC film on the top of the PS layer by a RTCVD system to form vertical type PN junction and metal-semiconductor-metal (MSM) photodiodes . For the PN junction diode, the main absorbing region is located on the PS layers. The diode exhibits a responsivity of 0.41A/W and 60.22% quantum efficiency. Under room temperature, and irradiation of 6.5mW/cm2 fluorescent lamp, the diode has a photo to dark current ratio of 393.83.Which is nearly 4 times compared to the counterpart with SiC/c-Si structure. While in the MSM structure photodiode, due to the high resistance of the PS layers, the SiC film becomes the main absorbing layers, and has a responsivity of 0.20A/W and 44.62% quantum efficiency. The results indicate the SiC films deposited on the PS with multi-porosity, have better properties for developing high performance photo-detecting device.

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