Thermal transport in beta-gallium oxide thin-films using non-gray Boltzmann transport equation

Nitish Kumar; Matthew C Barry; Satish Kumar

doi:10.1088/1361-648X/ac413e

Thermal transport in beta-gallium oxide thin-films using non-gray Boltzmann transport equation

J Phys Condens Matter. 2021 Dec 24;34(10). doi: 10.1088/1361-648X/ac413e.

Authors

Nitish Kumar¹, Matthew C Barry¹, Satish Kumar¹

Affiliation

¹ G.W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, United States of America.

PMID: 34879360
DOI: 10.1088/1361-648X/ac413e

Abstract

Phonon transport inβ-Ga₂O₃thin films and metal-oxide field effect transistors (MESFETs) are investigated using non-gray Boltzmann transport equations (BTEs) to decipher the effect of ballistic-diffusive phonon transport. The effects of domain size, and energy dissipation to various phonon modes and subsequent phonon-phonon energy exchange on the thermal transport and temperature distribution is investigated using non-gray BTE. Our analysis deciphered that domain size plays a major role in thermal transport inβ-Ga₂O₃but energy dissipation to various phonon modes and subsequent phonon-phonon energy exchange does not affect the temperature field significantly. Phonon transport inβ-Ga₂O₃MESFETs on diamond substrate is investigated using coupled non-gray BTE and Fourier model. It is established that the ballistic effects need to be considered for devices withβ-Ga₂O₃layer thickness less than 1 μm. A non-gray phonon BTE model should be used near hotspot in the thinβ-Ga₂O₃layer as the Fourier model may not give accurate temperature distribution. The results from this work will help in understanding the mechanism of phonon transport in theβ-Ga₂O₃thin films and energy efficient design of its FETs.

Keywords: field effect transistors (FETs); non-gray Boltzmann transport equation (BTE); phonon transport; thermal transport; wide bandgap materials; β-Ga2O3.