Title :
Thermal Properties of AlGaN/GaN HFETs on Bulk GaN Substrates
Author :
Killat, N. ; Montes, M. ; Pomeroy, J.W. ; Paskova, T. ; Evans, K.R. ; Leach, J. ; Li, X. ; Özgür, Ü ; Morkoç, H. ; Chabak, K.D. ; Crespo, A. ; Gillespie, J.K. ; Fitch, R. ; Kossler, M. ; Walker, D.E. ; Trejo, M. ; Via, G.D. ; Blevins, J.D. ; Kuball, M.
Author_Institution :
H.H. Wills Phys. Lab., Univ. of Bristol, Bristol, UK
fDate :
3/1/2012 12:00:00 AM
Abstract :
Micro-Raman thermography, microphotoluminescence spectroscopy, and thermal simulation were used to study the thermal properties of AlGaN/GaN heterostructure field-effect transistors grown on semi-insulating bulk GaN substrates. A bulk GaN thermal conductivity of 260 was determined from temperature measurements on operating devices in combination with finite-difference thermal simulations. This is significantly higher than typical thin GaN epilayer thermal conductivities, due to a lower dislocation density in bulk GaN. Despite the thermal conductivity of bulk GaN being lower than that of SiC, transistors on bulk GaN exhibited a similar thermal resistance as GaN-on-SiC devices, attributed to the absence of a thermal boundary resistance between the device epilayers and substrate for GaN-on-GaN devices.
Keywords :
III-V semiconductors; aluminium compounds; gallium compounds; high electron mobility transistors; substrates; thermal conductivity; wide band gap semiconductors; AlGaN-GaN; HFET; bulk substrates; epilayer thermal conductivities; finite-difference thermal simulations; heterostructure field-effect transistors; microRaman thermography; microphotoluminescence spectroscopy; temperature measurements; thermal boundary resistance; thermal properties; Aluminum gallium nitride; Conductivity; Gallium nitride; HEMTs; Substrates; Temperature measurement; Thermal conductivity; AlGaN/GaN heterostructure field-effect transistor (HFET); Raman thermography; bulk GaN thermal conductivity; thermal boundary resistance;
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/LED.2011.2179972