Ultrafast Removal of LO-Mode Heat From a GaN-Based Two-Dimensional Channel

• Published in: Proceedings of the IEEE Vol. 98; no. 7; pp. 1118 - 1126
• Main Authors: Matulionis, Arvydas, Liberis, Juozapas, Matulioniene, Ilona, Ramonas, Mindaugas, Sermuksnis, Emilis
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.07.2010; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Channels; Density; Electric power generation; Electron density; Electron gas; Electron optics; Frequency; Gallium nitrides; GaN-based channels; HEMTs; heterostructure field-effect transistor; MODFETs; phonon-plasmon resonance; Phonons; Power supplies; Resonance; Temperature dependence; Two dimensional; two-dimensional electron gas; Ultrafast optics; Voltage
• ISSN: 0018-9219; 1558-2256
• DOI: 10.1109/JPROC.2009.2029877

Dissipation of the Joule heat, accumulated in non-equilibrium longitudinal optical (LO) phonon modes, is considered in terms of LO-phonon lifetime. The dependence of the lifetime on electron density, hot-electron temperature, and supplied electric power are presented for a voltage-biased GaN-based channel with a two-dimensional electron gas (2DEG). An improved understanding of conversion of LO phonons into acoustic and other phonons is reached. A nonmonotonous dependence of the lifetime on the electron density is observed. The optimal 2DEG density for ultrafast decay of the LO-mode heat is estimated and explained in terms of LO-phonon-plasmon resonance. A new limitation of the frequency performance is predicted for heterostructure field effect transistors under the off-resonance conditions of operation. The shortest hot-phonon lifetime of ~60± 20 fs is found, at a high level of supplied power, in nearly lattice matched InAlN/AlN/GaN.