Impact of Gate-Aperture Overlap on the Channel-Pinch Off in InGaAs/InGaN-Based Bonded Aperture Vertical Electron Transistor

• Published in: IEEE electron device letters Vol. 34; no. 12; pp. 1500 - 1502
• Main Authors: Lal, Shalini, Jing Lu, Gupta, Geetak, Thibeault, Brian J., DenBaars, Steven P., Mishra, Umesh K.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.12.2013; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Apertures; Applied sciences; Bonded aperture vertical electron transistor (BAVET); current aperture vertical electron transistor (CAVET); direct wafer-bonding; Electric breakdown; Electronics; Exact sciences and technology; field-plate; Gallium nitride; GaN; Gate leakage; impact-ionization; Indium gallium arsenide; InGaAs; Microelectronic fabrication (materials and surfaces technology); Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Transistors; vertical transistor; Ternary compound; Binary compound; Stacking; impact-ionization; Blocking layer; Gallium nitride; III-V compound; direct wafer-bonding; Wafer bonding; Direct method; InGaAs; field-plate; Microelectronic fabrication; GaN; Bonded aperture vertical electron transistor (BAVET); Impact ionization; Indium nitride; Vertical transistor; current aperture vertical electron transistor (CAVET); Wafer; Damaging
• ISSN: 0741-3106; 1558-0563
• DOI: 10.1109/LED.2013.2286954

A unipolar transistor consisting of an In 0.53 Ga 0.47 As (InGaAs) channel and a III-Nitride (III-N)-based drain-region with a maximum on-current of 192 mA/mm is reported. This unique device is realized by employing wafer-bonding to a current aperture vertical electron transistor and is referred to as a wafer-bonded aperture vertical electron transistor (BAVET). An In 0.52 Al 0.48 As/InGaAs layer-stack is used for the gate-barrier and channel regions, while the aperture, current-blocking-layer (CBL) and drift regions are part of the III-N layer structure. This letter investigates the factors affecting the off-characteristics of a BAVET by varying the overlaps of the gate-CBL (L GO ) and gate-aperture (L GA ) regions. A dual-functionality of modulating the channel and providing a field-plate effect is realized using the L GO and L GA parts of the gate, respectively. We report that the improvement in channel-pinch off is a stronger function of L GA than it is of L GO . A weak pinch off in the InGaAs channel is shown to be the consequence of impact-ionization leading to channel-breakdown, and using a gate-aperture overlap dramatically improves both the pinch off and off-state-breakdown in BAVETs.