设计了一种InGaAs/InAlAs雪崩光电二极管(APD),并利用MEDICI软件进行了模拟仿真。器件采用背入射探测方式。雪崩增益区采用埋层设计,省略了保护环等结构;并使用双层掺杂,有效降低了增益区电场的梯度变化。由于结构简单,因此仅需要利用分子束外延(MBE)生长精确控制每层结构即可。由于InAlAs材料的空穴与电子的离化率有较大的差异,因此器件具有较低的噪声因子。 An InGaAs / InAlAs avalanche photodiode (APD) was designed and simulated by MEDICI software. The device uses back-fire detection method. The avalanche gain region is buried layer design, omitting the guard ring and other structures; and the use of double doping, effectively reducing the gain region gradient of the electric field. Due to its simple structure, it is only necessary to precisely control each layer structure by molecular beam epitaxy (MBE) growth. Because InAlAs material hole and electron ionization rate are quite different, so the device has a lower noise factor.