Enhanced gain-bandwidth product and performance in thin heterostructure avalanche photodiodes

In this paper, the initial-energy and bandgap-boundary mechanisms are shown to improve the gain-bandwidth product (GBP) beyond the limits previously known. Here we use the rationale of the modified dead-space multiplication theory (MDSMT) for gain noise, which captures both the initial-energy and the bandgap-boundary effects in heterostructure APDs, to extend our recursive technique for the prediction of the mean impulse response to arbitrary heterostructure APDs. The improvement in GBP due to the initial energy effect is clear. It is observed that the initial energy effect becomes more significant as the width of the multiplication layers decrease.