Selective injection AlGaN/GaN heterojunction bipolar transistors with patterned regrown base contacts

2023/09/18 by Chandan Joishi, Sheikh Ifatur Rahman, Joishi, Chandan +7
Engineering · Physics and Astronomy · #Acoustic Wave Resonator Technologies #Applied Physics (physics.app-ph) #FOS: Physical sciences #GaN-based semiconductor devices and materials #Radio Frequency Integrated Circuit Design

paper · pdf · doi:10.48550/arxiv.2309.09886

openalex publication_date 2023/09/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

We demonstrate graded AlGaN/GaN heterojunction bipolar transistors (HBTs) with selective injection of minority carriers across a p-GaN base and patterned regrown base contacts. The selective injection design regulates minority carrier transport under emitter-base forward bias through a thin base region, while thick and highly doped p⁺ GaN regrown layers patterned alongside the thin base regions are utilized to lower the base contact resistance. With SiO₂ employed as a spacer between the emitter and the p⁺ regrown layers, the device with an interdigitated emitter/base-contact stripe design displayed a maximum collector current density (I_C) of 101 kA/cm², a maximum current gain (β) of 70 at I_C ∼ 1 kA/cm² and ∼ 11 for I_C > 50 kA/cm². The reported results demonstrate the potential of the selective injection approach to break the long-existing HBT design tradeoff between base resistance and current gain for next-generation radio frequency and mm-Wave applications.

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