Abstract

A comparison of the multiquantum well, staircase, and doped quantum well avalanche photodiodes is presented based on the calculated gain and excess noise factor. The gain is determined from the electron and hole ionization probabilities per stage derived from an ensemble Monte Carlo calculation. The Monte Carlo calculation is particularly well adapted to study impact ionization in APDs since it includes the full details of the conduction and valence bonds as well as collisional broadening. Various device geometries are examined (different layer widths, dopings, and overall effective field strength) among the three different device types. In each case an optimized structure, in terms of the overall gain and excess noise factor, is presented. The results for devices made from the GalnAs/AllnAs material system indicate that the doped quantum well device gives the largest gain at the lowest excess noise factor of the three device types.

© 1986 Optical Society of America