Si~C-SiC Multiple Quantum Barrier High Speed, Wide-Band Avalanche Photodiodes

The optoelectronic properties of Si~3C-SiC hetero-junction based multiple quantum barrier (MQB) avalanche photodiodes (APDs) have been studied. The MQB APDs are found to be highly proficient devices for long wavelength detection. The number of quantum barriers (QBs) in MQB APDs has been varied and corresponding multiplication gain and excess noise factor (ENF) are calculated. Results indicate significantly reduced ENF of MQB devices as compared to the flat Si devices. It has also been clearly observed that reduction of ENF in MQB devices is directly related to the number of QBs. Current response of MQB APDs has been calculated for narrow rectangular shaped optical pulses of pulse-width of the order of picoseconds (ps) of wavelength 850 μm. Lastly, the time-domain current response has been Fourier transformed in order to obtain frequency response of the device. MQB APDs are found to be appreciably faster time and wider frequency responses than the flat Si APDs.