Numerical simulation study on In_0.53Ga_0.47As/In_0.52Al_0.48As avalanche photodiode

An analytical modeling of In0.53Ga0.47As/In0.52Al0.48As avalanche photodiode(APD) was proposed with In0.52Al0.48As charge layer between the absorption and multiplication region(SACM). Numerical study and theoretical analysis were performed to design a high performance In0.53Ga0.47As/In0.52Al0.48As APD. An In0.52Al0.48As barrier layer was adopted to block minority carriers originated from contact regions in our APD. Simultaneously, double-doped multiplication layer was used to improve the electric field gradient change of the multiplication region and reduce the dark current. In addition, the influence of different doping level and different thickness of every layer on the energy band, the electric field distribution, breakdown voltage and current-voltage characteristics were also investigated by using device simulation software ATLAS from SILVACO international. The photodetector exhibits a high responsivity of 0.9 A/W at the unity gain. The gain is 23.4 at the operating voltage(0.9 Vb). Furthermore, the dark current is only in the nano-ampere orders of magnitude at 0.9 Vb.