Influence of a charge region on the operation of InGaAs/InAlAs/InP avalanche photodiodes

Avalanche photodiodes (APDs) operating at 1.55 μm wavelength are used in many different applications. Therefore, specialized devices with modified electrical characteristics are often strongly needed. In order to design and produce such structures, advanced modeling techniques and computer aided design (CAD) software are utilized. In the paper, modeling results of avalanche photodiodes with separated regions of absorption, grading, charge and multiplication (SAGCM) are presented. Simulations of diode structures were performed using APSYS software developed by Crosslight. Extensive calculations allowed for the detailed analysis of individual regions of the device and the determination of their influence on diode characteristics. Simulations showed a pronounced influence of the charge region on characteristics and performance of the device. Changes of the doping level of this layer exhibited strong modification in the band-to-band tunneling effect. Simultaneously it influenced the characteristics related to the Zener effect and carrier transport.