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

• Published in: ACS applied electronic materials Vol. 1; no. 8; pp. 1387 - 1399
• Main Authors: Siddique, Anwar, Ahmed, Raju, Anderson, Jonathan, Nazari, Mohammad, Yates, Luke, Graham, Samuel, Holtz, Mark, Piner, Edwin L
• Format: Journal Article
• Language: English; Japanese
• Published: American Chemical Society 27-08-2019
• Subjects: AlGaN/GaN HEMT; GaN; CVD diamond; TBR; HRXRD; RSM; biaxial stress
• ISSN: 2637-6113; 2637-6113
• DOI: 10.1021/acsaelm.9b00131

Integration of diamond and AlGaN/GaN high-electron mobility transistors (HEMTs) terminated with an in situ grown SiN x 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 SiN x /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 SiN x dielectric adhesion layer was observed at the SiN x /diamond interface. Using time domain thermoreflectance (TDTR), the effective isotropic thermal conductivity of the diamond was determined to be 176–35 +40 W/m·K. The effective thermal boundary resistance of the diamond/GaN interface (including the SiN x and additional layers) was 52.8–3.2 +5.1 m2·K/GW.