InPSb/InAs BJT DEVICE AND METHOD OF MAKING

摘要

Bipolar junction transistor (BJT) devices, particularly bipolar transistor (HBT) devices, and methods of making same are described. A combination of InPSb and p-type InAs is used to create extremely high speed bipolar devices which, due to reduced turn-on voltages, lend themselves to circuits having drastically reduced power dissipation. The described HBTs are fabricated on InAs or GaSb substrates, power dissipation. The described HBTs are fabricated on InAs when on an InAs substrate, and as InAsSb when on a GaSb substrate. The collector may be the same as the base to form a single heterojunction bipolar transistor (DHBT). Heterojunctions preferably include a grading layer, which may be implemented by continuously changing the bulkmaterial composition, or by forming a chirped superlattice of alternating materials. The grading layer preferably has delta doping planes near its ends to form an electrostatic gradient offsetting the quasi-electric field variation due to the changes in material composition, whereby effective conduction band offset may be substantially eliminated to facilitate speed, and valence band offset increased proportionally to enhance gain.