Accession Number : ADA553600


Title :   The Impact of GaN/Substrate Thermal Boundary Resistance on a HEMT Device


Descriptive Note : Conference paper


Corporate Author : ARMY RESEARCH LAB ADELPHI MD


Personal Author(s) : Nochetto, Horacio C ; Jankowski, Nicholas R ; Bar-Cohen, Avram


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a553600.pdf


Report Date : Nov 2011


Pagination or Media Count : 10


Abstract : The present work uses finite element thermal simulations of Gallium Nitride High Electron Mobility Transistors (GaN HEMTs) to evaluate the impact of device design parameters on the junction temperature. In particular the effects of substrate thickness, substrate thermal conductivity, GaN thickness, and GaN-to-substrate thermal boundary resistance (TBR) on device temperature rise are quantified. In all cases examined, the TBR was a dominant factor in overall device temperature rise. It is shown that a TBR increase can offset any benefits offered through a more conductive substrate and that there exists a substrate thickness independent of TBR which results in a minimum junction temperature. Additionally, the decrease of GaN thickness only provides a thermal benefit at small TBRs. For TBRs on the order of 10(exp -4) sq cm K/W or greater, decreasing the GaN thickness can actually increase the temperature as the heat from the highly localized source is not sufficiently spread out before crossing the GaN-substrate boundary. The tradeoff between GaN heat spreading, substrate heat spreading, and temperature rise across the TBR results in a GaN thickness with minimum total temperature rise. For the TBR values of 10(exp -4) sq cm K/W and 10(exp -3) sq cm K/W these GaN thicknesses are 0.8 microns and 9 microns respectively.


Descriptors :   *HIGH ELECTRON MOBILITY TRANSISTORS , *SUBSTRATES , CRYSTAL LATTICES , GALLIUM NITRIDES , MODELS , SILICON CARBIDES , SYMPOSIA , THERMAL BOUNDARY LAYER , THERMAL CONDUCTIVITY


Subject Categories : Electrical and Electronic Equipment
      Electricity and Magnetism
      Thermodynamics


Distribution Statement : APPROVED FOR PUBLIC RELEASE