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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In P材料的差异更大,因此器件的噪声因子也较低。
The analytical model of the SACM In0.53Ga0.47As / In0.52Al0.48As avalanche photodiode (APD) was established. The high performance In0.53Ga0.47As / In0.52Al0.48As APD was designed by numerical and theoretical analysis. In the device design, on the one hand, the In0.52Al0.48As barrier layer is added to block the diffusion of minority carriers in the contact layer, thereby reducing the generation of dark current; on the other hand, the avalanche multiplication region adopts a double- , Which optimizes the electric field gradient distribution in the device multiplication region. Finally, the influences of the avalanche multiplication layer, charge layer and absorption layer doping level and thickness on the electric field distribution, breakdown voltage, IV characteristics and DC gain of the device are systematically studied and analyzed by ATLAS software. The optimized APD has a unity gain of 0.9 A / W, a gain of 23.4 at operating voltage (0.9 Vb), and a nano-ampere rating (@ 0.9 Vb) of operating dark current. As the In0.52Al0.48As material has a higher electron-hole collision ionization ratio than the InP material, the device has a lower noise figure.