| Summary: | 碩士 === 國立臺灣大學 === 光電工程學研究所 === 92 === In this thesis, the novel metal-oxide-semiconductor (MOS) tunneling diodes with high leakage current were utilized as photodetectors. The leakage of inversion carrier through ultrathin oxide makes the device to operate in the deep depletion region. The dark current is limited by the thermal generation process and can be reduced by the high growth temperature of oxide.
In order to increase the speed of the MOS tunneling photodetectors, the novel fully-depleted silicon-on-insulator (SOI) MOS photodetector is proposed. For devices with 1020 cm-3 buffer layer doping, the device can reach high bandwidth (22 GHz) and are fully compatible with ultra-large scale integration (ULSI) technology. For thin devices, the transit time can be determined by the drift mechanism. For thick devices, however, the diffusion mechanism is needed to describe the device behavior. DBR (distributed Bragg reflector) model is used to design the device for better responsivity.
The metal-insulator-semiconductor light emission diode (MIS LED) using high k insulators is successfully demonstrated. The enhancement of quantum external efficiency of MIS LED is accomplished well due to more quantum confinement holes created by larger electric field on Si. From the simulations, it is confirmed that the electric field on Si is increased when HfO2 replaced SiO2. The long wavelength EL spectrum is observed for the high k LED with many interface states. The normalized EL spectrum of MOS LED and high k LED are similar. The quantum efficiency of high k LED is 2 * 10-6, which is about ten times larger than oxide LED.
Surface plasmon is applied on MOS LED for better light intensity. By controlling the size of hole array, we can have enhanced transmission for silicon emitted light through Aluminum film.
These simple and high performance Si-based photodetectors together with other devices can be used as building blocks for the future optical signal process and the optoelectronic applications on Si chips.
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