Description

Epitaxial Structure
The AlGaAs/GaAs HBT epitaxial wafer features a vertical three-terminal device architecture. The emitter region utilizes lightly doped wide-bandgap AlₓGa₁₋ₓAs semiconductor material, with aluminum composition (x) typically optimized at ~0.25 (exceeding this value introduces deep levels in n-type AlGaAs, increasing emitter junction capacitance). The base region employs heavily doped narrow-bandgap material. Grown on semi-insulating substrates, this structure enables effective device isolation and interconnects while maintaining excellent lattice matching within the AlGaAs/GaAs material system.

Performance Characteristics
High-frequency/Low-noise Operation: The bandgap discontinuity (ΔE_g > 0) permits higher base doping concentrations than the emitter, significantly reducing base resistance and emitter-base capacitance. This yields exceptional high-frequency response, switching speed, and noise performance.

High Current Gain: With properly engineered ΔE_g, these HBTs achieve DC current gains (β) typically exceeding 60, meeting stringent signal amplification requirements across diverse applications.

Target Applications
As a principal GaAs-based HBT variant, devices fabricated from this epitaxial wafer demonstrate high power density, low phase noise, excellent linearity, and single-supply operation capability. Key applications include:

Low-frequency wireless systems
Wireless regional area networks (WRAN)
High-efficiency power amplifiers
3G/4G/5G/Wi-Fi/GSM/HPUE mobile devices