In0.53Ga0.47As/In0.52Al0.48As雪崩光电二极管的数值模拟研究

建立了SACM型In0.53Ga0.47As/In0.52Al0.48As雪崩光电二极管(APD)的分析模型,通过数值研究和理论分析设计出高性能的In0.53Ga0.47As/In0.52Al0.48As APD。器件设计中,一方面添加了In0.52Al0.48As势垒层来阻挡接触层的少数载流子的扩散,进而减小暗电流的产生;另一方面,雪崩倍增区采用双层掺杂结构设计,优化了器件倍增区的电场梯度分布。最后,利用ATLAS软件较系统地研究并分析了雪崩倍增层、电荷层以及吸收层的掺杂水平和厚度对器件电场分布、击穿电压、IV特性和直流增益的影响。优化后APD的单位增益可以达到0.9 A/W,在工作电压(0.9 Vb)下增益为23.4,工作暗电流也仅是纳安级别(@0.9 Vb)。由于In0.52Al0.48As材料的电子与空穴的碰撞离化率比InP材料的差异更大,因此器件的噪声因子也较低。

Numerical simulation study on In0.53Ga0.47As/In0.52Al0.48As 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.