Signature of Hot Phonons in Reliability of Nitride Transistors and Signal Delay
A. Matulionisa, J. Liberisa, I. Matulionienėa, E. Šermukšnisa, J.H. Leachb, M. Wub, X. Nib and H. Morkoçb
aSemiconductor Physics Institute, Centre for Physical Sciences and Technology, Vilnius, Lithuania
bDepartment of Electrical and Computer Engineering, Virginia Commonwealth University, Richmond, VA, USA
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Lifetime of non-equilibrium (hot) phonons in biased GaN heterostructures with two-dimensional electron gas channels was estimated from hot-electron fluctuations. Dependence of the lifetime on the electron density is not monotonous - the resonance-type fastest decay serves as a signature of hot phonons. The signature is resolved in nitride heterostructure field effect transistors when the gate voltage is used to change the channel electron density. The transistor cut-off frequency decreases on both sides of the resonance in agreement with the enhanced electron scattering caused by longer hot-phonon lifetimes. The signature is also noted in device reliability experiment: the enhanced temperature of hot phonons, possibly, triggers formation of new defects and accelerates device degradation.
DOI: 10.12693/APhysPolA.119.225
PACS numbers: 72.70.+m, 73.50.Fq, 73.61.Ey