Design Space of III-N Hot Electron Transistors Using AlGaN and InGaN Polarization-Dipole Barriers

• Published in: IEEE electron device letters Vol. 36; no. 1; pp. 23 - 25
• Main Authors: Gupta, Geetak, Laurent, Matthew, Li, Haoran, Suntrup, Donald J., Acuna, Edwin, Keller, Stacia, Mishra, Umesh K.
• Format: Journal Article
• Language: English
• Published: IEEE 01.01.2015
• Subjects: Aluminum gallium nitride; Current measurement; Gallium nitride; Integrated circuits; Modulation; Substrates; Transistors; hot electron transistors; GaN
• ISSN: 0741-3106; 1558-0563
• DOI: 10.1109/LED.2014.2373375

Transistor operation by common emitter (CE) current modulation is shown for the first time in III-N hot electron transistors (HETs). The emitter and collector barriers (<inline-formula> <tex-math notation="LaTeX">\phi _{\mathrm {\mathbf {BE}}} </tex-math></inline-formula> and <inline-formula> <tex-math notation="LaTeX">\phi _{\mathrm {\mathbf {BC}}} </tex-math></inline-formula>) are implemented using Al 0.45 Ga 0.55 N and In 0.1 Ga 0.9 N layers as polarization dipoles, respectively. CE modulation is achieved by increasing the E-B barrier height beyond the B-C barrier height by increasing the Al 0.45 Ga 0.55 N thickness (<inline-formula> <tex-math notation="LaTeX">t </tex-math></inline-formula>). Similar CE performance is seen in the identical HET structures grown on both bulk GaN and sapphire. A maximum <inline-formula> <tex-math notation="LaTeX">\alpha </tex-math></inline-formula> of <inline-formula> <tex-math notation="LaTeX">\sim 0.3 </tex-math></inline-formula> is achieved using a GaN base thickness of 10 nm. The InGaN dipole used as the collector barrier is shown to be instrumental in enabling ohmic base contacts, low base sheet resistance, and low collector leakage, simultaneously.