Optimization of direct current performance in terahertz InGaAs/InP double-heterojunction bipolar transistors

Abstract

As the dimensions of In0.53Ga0.47As/InP double-heterojunction bipolar transistors (DHBTs) scale for terahertz applications, the DC current (β) decreases. To improve the DC performance in such scaled devices, we analyze three modified HBT geometries: a HBT with a surface pulse-doped layer in the base, a HBT having this pulse-doped layer under the emitter junction and under the base contact, but with it removed by etching in the region between the base and emitter contacts, and a device, necessarily fabricated by regrowth, in which the pulsed doped layer is present under only the base contacts. Based on a drift-diffusion/recombination model, carrier transport in the DHBT base is simulated and the corresponding β is computed using TCAD software. The structures with a pulse doped layer can attain β = 31 ∼ 39 at 100 nm emitter width. The structures with a trench between the base contact and emitter show β = 39 ∼ 54 at 100 nm emitter width. Finally, the structure with recessed base-emitter junction and regrown emitter demonstrate β = 62–119 at 100 nm emitter width.

Impact of phonons and spin-orbit coupling on Auger recombination in InAs

“…It reduces the efficiency of light-emitting devices at high power and has been shown to play a significant role in the efficiency-droop and green-gap problems of nitride light-emitting diodes [1][2][3]. Auger processes also contribute to efficiency loss in photovoltaics [4] and limit the direct current performance of bipolar transistors [5]. Auger recombination is particularly critical in narrow-gap semiconductors such as InAs-based heterostructures.…”

Composition and doping control for metal–organic chemical vapor deposition of InP-based double heterojunction bipolar transistor with hybrid base structure consisting of GaAsSb contact and InGaAsSb graded layers

“…Another approach is to use a base contact layer. 10,11) In this structure, a very thin layer (a few nanometers) with a high hole concentration is inserted between the emitter and intrinsic base. Since the base electrode contacts the high-hole-concentration layer directly, the base contact resistance is lowered.…”