Design and Simulation of InGaN/GaN p-i-n Photodiodes
Résumé
InGaN ternary alloys with their band gaps varying from 0.7 to 3.4eV, are very promising for photodetector devices operating from UV to IR wavelength range. Using Silvaco-Atlas software, an In0.1Ga0.9N/GaN based p-i-n photodiode is designed and the J-V characteristics, the spectral responsivity, the frequency response and the cut-off frequency as a function of InGaN thickness are studied. The photodiode exhibits a high reverse breakdown voltage of 38V, a peak responsivity of 0.2AW(-1) at 0.343m wavelength and a cutoff frequency of 400MHz under an applied reverse bias voltage of 2V and for a 0.1m i-InGaN layer, in good agreement with simulated and experimental results found in literature. It is found that an optimum i-layer thickness of 1.5m for the maximum cutoff frequency of 4GHz attributed to the predominance of the limitation in capacitance effect on the cutoff frequency at low i-layer thickness and the transit time on the cuttoff frequency for high i-layer thickness. For this i-layer thickness, the highest peak responsivity about 0.244AW(-1) at 0.384m wavelength is achieved.