One-flux analysis of current blocking in double heterostructure bipolar transistors with composite collectors

We use the flux method of McKelvey, Longini, and Brody [Physical Review 123, 51 (1961)] to analyze current blocking in double heterostructure bipolar transistors (DHBTs) with composite collectors (CC). We include the effects of electron accumulation in the spacer layer in the collector, and show that this accumulation has severe effects at higher currents, imposing an intrinsic limit on the simplest CC design. We compare the results from the flux method with drift-diffusion simulations and measurements on InP/InGaAs/InP CC-DHBTs.