Theoretical and Experimental DC Characterization of InGaAs-Based Abrupt EmitterHBT's

摘要

The dc characteristics of InP/InGaAs and InAlAs/InGaAs HBT's with abrupt emitter-base junctions are studied using a thermionic-field emission boundary-condition model. The model incorporates tunneling and thermionic emission into a one-dimensional drift-diffusion numerical scheme and accounts for breakdown and bulk recombination mechanisms. The effects of abrupt heterojunction transport and electrical junction displacement on the current gain h sub FE and on the turn-on voltage are investigated. The simulations indicate that the spacer layer design has a profound effect on the dc behavior of these devices. A detailed performance comparison of different emitter structures indicates that InP-emitter HBT's show a more uniform h sub FE than InAlAs-emitter HBT's especially at low current densities. jg.