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Structure and Interface Analysis of Diamond on an AlGaN/GaN HEMT Utilizing an in Situ SiNx Interlayer Grown by MOCVD

MetadataDetails
Publication Date2019-07-19
JournalACS Applied Electronic Materials
AuthorsAnwar Siddique, Raju Ahmed, Jonathan Anderson, Mohammad Nazari, Luke Yates
InstitutionsGeorgia Institute of Technology, Texas State University
Citations49

Integration of diamond and AlGaN/GaN high-electron mobility transistors (HEMTs) terminated with an in situ grown SiNx interface layer via metal organic chemical vapor deposition is investigated. The effect of diamond growth on the structure and interface properties of the HEMT is studied using high-resolution X-ray diffraction, micro-Raman spectroscopy, atomic force microscopy, and scanning transmission electron microscopy (STEM). No structural or physical damage is observed to the HEMT device layers as a result of the hot filament chemical vapor deposition diamond fabrication process. The TEM cross section confirms the smooth and abrupt interface of in situ SiNx/AlGaN/GaN before and after the diamond growth, with no detectable carbon diffusion into the GaN buffer layer. However, selective degradation of the in situ SiNx dielectric adhesion layer was observed at the SiNx/diamond interface. Using time domain thermoreflectance (TDTR), the effective isotropic thermal conductivity of the diamond was determined to be 176-35+40 W/mĀ·K. The effective thermal boundary resistance of the diamond/GaN interface (including the SiNx and additional layers) was 52.8-3.2+5.1 m2Ā·K/GW.