Analytical approach to selection of the optimum structure of avalanche heterophotodiodes based on direct bandgap semiconductors

Abstract

Using an analytical model of the avalanche heterophotodiode (AHPhD), principles of selection of its optimal structure are given. The model is based on analytical expressions for the field of the avalanche breakdown of the p–n heterostructure and the interband tunnel current in it, which determines the minimum noise level in the AHPhDs based on direct bandgap semiconductors. To reduce the tunnel current, it is necessary to use a structure with separated absorption and multiplication regions. This approach allows one to analytically determine parameters of the structure in which the latter is implemented. In addition, it enables one to analytically determine such parameters and structures of “low–high–low” type that simultaneously provide both the minimum tunnel current and the minimum avalanche noise factor.