Submicrometer fully self-aligned AlGaAs/GaAs Heterojunction bipolar transistor

A novel submicrometer fully self-aligned AlGaAs/GaAs heterojunction bipolar transistor (HBT) for reducing parasitic capacitances and resistances is proposed. The fabrication process utilizes SiO
2
sidewalls for defining base electrode width and separating this electrode from both emitter and collector electrodes. Measured common-emitter current gain β for a fabricated HBT with 0.6 × 10-µm
²
emitter dimension and 0.7 × 10-µm
²
× 2 base dimension is 26 at 9 × 10
⁴
-A/cm
²
collector current density.