Skip to main content
OSTI.GOVU.S. Department of Energy Office of Scientific and Technical Information
U.S. Department of Energy
Office of Scientific and Technical Information
 

Reduced thermal resistance of Al-rich AlGaN HEMTs via top-side diamond integration

Journal Article · · APL Electronic Devices
DOI:https://doi.org/10.1063/5.0304018· OSTI ID:3009510
 [1];  [2];  [1];  [1];  [2];  [2];  [1];  [3];  [3];  [4];  [1];  [2];  [5];  [5];  [1];  [1];  [1];  [1]
  1. U.S. Naval Research Laboratory (NRL), Washington, DC (United States)
  2. Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
  3. Amentum Services, Inc., Oak Ridge, TN (United States); U.S. Naval Research Laboratory (NRL), Washington, DC (United States)
  4. National Research Council (NRC), Washington, DC (United States); U.S. Naval Research Laboratory (NRL), Washington, DC (United States)
  5. Univ. of Virginia, Charlottesville, VA (United States)
+ Show Author Affiliations
We report back-end-of-line growth of nanocrystalline diamond (NCD) on ultrawide bandgap (UWBG) high Al content aluminum gallium nitride (AlGaN) channel high electron mobility transistors for thermal management. A thin (∼15 nm) silicon nitride (SiNx) interlayer was deposited to protect the device surface before performing a low temperature (500 °C) NCD growth process in an attempt to protect the gates on these fully fabricated devices. Notably, atomic force microscopy showed that the maximum lateral grain size exceeded 300 nm even though the film thickness was ∼250 nm. Comparing electrical (DC) performance before and after NCD growth, the gate leakage increased by ∼102 after NCD growth. Despite the lower NCD growth temperature, intermixing of the Ni and Au was observed in the Schottky gate metal stack; however, we believe there is another mechanism, possibly hydrogen-related, that is responsible for the measured increase in gate leakage. Regarding thermal management, the device-level thermal resistance (quantified using the average gate temperature rise measured by thermoreflectance imaging) was reduced by 29% through the incorporation of the top-side diamond film. Using time-domain thermoreflectance, the thermal conductivity of the ≈250 nm thick NCD film was measured to be 45 ± 25 W m−1 K−1. This is expected to be at least 5× greater than the thermal conductivity of the thin disordered AlGaN alloy. There could also be a coupled electrothermal component contributing to the reduced temperature rise from electric field spreading and consequent heat spreading. This study demonstrates a promising first step toward device-level thermal management of high power UWBG Al-rich AlGaN devices.
Research Organization:
Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
Sponsoring Organization:
USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Basic Energy Sciences (BES)
Grant/Contract Number:
NA0003525
OSTI ID:
3009510
Report Number(s):
SAND--2025-15309J; 1784242
Journal Information:
APL Electronic Devices, Journal Name: APL Electronic Devices Journal Issue: 4 Vol. 1; ISSN 2995-8423
Publisher:
AIP PublishingCopyright Statement
Country of Publication:
United States
Language:
English

References (46)

Al‐Rich AlGaN Transistors with Regrown p‐AlGaN Gate Layers and Ohmic Contacts journal March 2024
Low Thermal Resistance of Diamond‐AlGaN Interfaces Achieved Using Carbide Interlayers journal October 2024
Ultrawide-Bandgap Semiconductors: Research Opportunities and Challenges journal December 2017
The CVD of Nanodiamond Materials journal July 2008
Ohmic contacts to Al-rich AlGaN heterostructures: Ohmic contacts to Al-rich AlGaN heterostructures journal June 2017
Reliability behavior of GaN HEMTs related to Au diffusion at the Schottky interface journal May 2009
Control of the in-plane thermal conductivity of ultra-thin nanocrystalline diamond films through the grain and grain boundary properties journal January 2016
Stability of AlGaN/GaN heterostructures after hydrogen plasma treatment journal February 2017
Orders of magnitude reduction in the thermal conductivity of polycrystalline diamond through carbon, nitrogen, and oxygen ion implantation journal February 2020
GaN-based HEMTs tested under high temperature storage test journal September 2011
Electrical and structural dependence of operating temperature of AlGaN/GaN HEMTs journal June 2013
Relative effectiveness of high-k passivation and gate-connected field plate techniques in enhancing GaN HEMT breakdown journal July 2020
Thermal conductivity of ultra-wide bandgap thin layers – High Al-content AlGaN and β -Ga2O3 journal February 2020
Analysis of heat flow in layered structures for time-domain thermoreflectance journal December 2004
Thermal transport and grain boundary conductance in ultrananocrystalline diamond thin films journal June 2006
Interpreting picosecond acoustics in the case of low interface stiffness journal November 2012
AlGaN channel field effect transistors with graded heterostructure ohmic contacts journal September 2016
Tutorial: Time-domain thermoreflectance (TDTR) for thermal property characterization of bulk and thin film materials journal October 2018
Multidimensional thermal analysis of an ultrawide bandgap AlGaN channel high electron mobility transistor journal October 2019
Nanoscale electro-thermal interactions in AlGaN/GaN high electron mobility transistors journal January 2020
Simultaneous thickness and thermal conductivity measurements of thinned silicon from 100 nm to 17 μm journal May 2021
Measuring sub-surface spatially varying thermal conductivity of silicon implanted with krypton journal August 2022
A review of thermoreflectance techniques for characterizing wide bandgap semiconductors’ thermal properties and devices’ temperatures journal December 2022
Reduced temperature in lateral (AlxGa1−x)2O3/Ga2O3 heterojunction field effect transistor capped with nanocrystalline diamond journal April 2024
Electrothermal enhancement of β-(AlxGa1−x)2O3/Ga2O3 heterostructure field-effect transistors via back-end-of-line sputter-deposited AlN layer journal December 2024
Integration of top-side low-temperature diamond on AlGaN/GaN RF HEMT for device-level cooling journal May 2025
Temperature dependent characterization of 140–180 nm AlGaN/GaN HEMTs using DC and small-signal RF measurements journal August 2025
Hydrogen effects on the thermal conductivity of delocalized vibrational modes in amorphous silicon nitride (a−SiNx:H) journal March 2021
Thermal conductivity of AlxGa1−xN (0≤x≤1) epitaxial layers journal October 2022
Operation Up to 500 °C of Al 0.85 Ga 0.15 N/Al 0.7 Ga 0.3 N High Electron Mobility Transistors journal January 2019
Reduced Self-Heating in AlGaN/GaN HEMTs Using Nanocrystalline Diamond Heat-Spreading Films journal January 2012
Transient Thermoreflectance for Gate Temperature Assessment in Pulse Operated GaN-Based HEMTs journal September 2016
Ultrafast Thermoreflectance Imaging and Electrothermal Modeling of β-Ga 2 O 3 MESFETs journal April 2020
The Impact of Bias Conditions on Self-Heating in AlGaN/GaN HEMTs journal January 2013
Numerical Analysis of Breakdown Voltage Enhancement in AlGaN/GaN HEMTs With a High-$k$ Passivation Layer journal March 2014
Influence of Field-Plate Configuration on Power Dissipation and Temperature Profiles in AlGaN/GaN on Silicon HEMTs journal August 2015
Direct Observation of Self-Heating in III–V Gate-All-Around Nanowire MOSFETs journal November 2015
Thermal Performance of GaN/Si HEMTs Using Near-Bandgap Thermoreflectance Imaging journal March 2020
Effect of High Temperature on the Performance of AlGaN/GaN T-Gate High-Electron Mobility Transistors With ~140-nm Gate Length journal March 2024
Effect of Hydrogen on Electrical Characteristics of AlGaN/GaN HEMTs After HTO Stress journal October 2024
Thermal Phenomena in Nanoscale Transistors journal June 2006
Device-Level Multidimensional Thermal Dynamics With Implications for Current and Future Wide Bandgap Electronics journal May 2020
Al-rich AlGaN based transistors journal March 2020
AlGaN Channel High Electron Mobility Transistors: Device Performance and Power-Switching Figure of Merit journal May 2008
Ultrawide-bandgap semiconductors: An overview journal December 2021
Growth of microcrystalline diamond films after fabrication of GaN high-electron-mobility transistors for effective heat dissipation journal June 2021

Similar Records

The impact of pulse width modulation on heat accumulation in AlGaN channel HEMTs
Journal Article · Thu Jul 17 20:00:00 EDT 2025 · APL Electronic Devices · OSTI ID:2999175
Structural, optical, and thermal properties of BN thin films grown on diamond via pulsed laser deposition
Journal Article · Tue Sep 19 20:00:00 EDT 2023 · Physical Review Materials · OSTI ID:2421834
Multidimensional thermal analysis of an ultrawide bandgap AlGaN channel high electron mobility transistor
Journal Article · Sun Oct 06 20:00:00 EDT 2019 · Applied Physics Letters · OSTI ID:1570273

Related Subjects