Low current-blocking InGaAs/InP DHBT grown by solid-source MBE

Double heterojunction bipolar transistor (DHBT) of InP and related materials is getting more attention due to its potential applications in 40 Gbps optical communications and low voltage radio frequency integration circuits. For these applications, the DHBT has to have low offset voltage, high breakdown voltage while with low current blocking effect. In this work, we have demonstrated that InGaAs/InP DHBT satisfying the aforementioned characteristics can be obtained by using InGaAs spacers at the BE and BC junctions, and a highly doped n-type InP layer in the collector region. Since the epilayers are grown by solid source molecular beam epitaxy, the Be-doped base layer is of high carrier concentration, which is shown to be effective in reducing the current blocking effect.