Design and Simulation of InGaN/GaN p–i–n Photodiodes

摘要

InGaN ternary alloys with their band gaps varying from 0.7 to 3.4 eV, arernvery promising for photodetector devices operating from UV to IRrnwavelength range. Using Silvaco–Atlas software, an In_(0.1)Ga_(0.9)N/GaN basedrnp–i–n photodiode is designed and the J–V characteristics, the spectralrnresponsivity, the frequency response and the cut-off frequency as a functionrnof InGaN thickness are studied. The photodiode exhibits a high reversrnbreakdown voltage of 38 V, a peak responsivity of 0.2 AW~(-1) at 0.343 μmrnwavelength and a cutoff frequency of 400MHz under an applied reversernbias voltage of 2 V and for a 0.1 μm i-InGaN layer, in good agreement withrnsimulated and experimental results found in literature. It is found that anrnoptimum i-layer thickness of 1.5 μm for the maximum cutoff frequency ofrn4GHz attributed to the predominance of the limitation in capacitance effectrnon the cutoff frequency at low i-layer thickness and the transit time on therncuttoff frequency for high i-layer thickness. For this i-layer thickness, thernhighest peak responsivity about 0.244 AW~(-1) at 0.384 μm wavelength isrnachieved.