Submicron heterojunction bipolar transistors (HBTs) with maximum frequency of oscillation,/max, of 91 GHz have been fabricated using a self-aligned technique and a very heavily carbon-doped (lO20 cm-3) base layer. Since the quenching of photoluminescence (PL) intensity in heavily-doped GaAs is mainly due to nonradiative recombination in the bulk material, while contribution from surface recombination is negligible, the use of a heavily carbon-doped base layer in AlGaAs/GaAs HBTs minimizes the influence of surface recombination in the extrinsic base region. Thus, for HBTs with a heavily doped base layer, the “emitter size effect” (degradation of HBT current gain) is greatly reduced when the emitter width is scaled down to submicron (0.6 ¡j, m) dimensions.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)
- Integrated photoluminescence intensity
- Nonradiative recombination
- Surface recombination