The Effect of Strained Al0.7In0.3 As Emitter Layers on Abrupt N-p+ AllnAs-GaInAs Heterojunction Diodes and Heterojunction Bipolar Transistors

Strained AlxIn1−xAs/Ga0.47In0.53As heterojunction N-p+ diodes and heterojunction bipolar transistors (HBTs) have been grown on InP substrates by solid-source molecular-beam epitaxy, fabricated, and characterized. To determine the effects of the conduction-band discontinuity at the emitter-base heterojunction on turn-on voltage and ideality factor, a strained Al0.7In0.3As layer is inserted in the emitter near the base. Changes in transport across the junction are observed as a function of the strained-layer position and thickness. These results were used to implement strained emitter HBTs.