Thermal conductivity of crystalline AlN and the influence of atomic-scale defects
Abstract
Aluminum nitride (AlN) plays a key role in modern power electronics and deep-ultraviolet photonics, where an understanding of its thermal properties is essential. Here, we measure the thermal conductivity of crystalline AlN by the 3ω method, finding that it ranges from 674 ± 56 Wm−1 K−1 at 100 K to 186 ± 7 Wm−1 K−1 at 400 K, with a value of 237 ± 6 Wm−1 K−1 at room temperature. We compare these data with analytical models and first-principles calculations, taking into account atomic-scale defects (O, Si, C impurities, and Al vacancies). We find that Al vacancies play the greatest role in reducing thermal conductivity because of the largest mass-difference scattering. Modeling also reveals that 10% of heat conduction is contributed by phonons with long mean free paths (MFPs), over ∼7 μm at room temperature, and 50% by phonons with MFPs over ∼0.3 μm. Consequently, the effective thermal conductivity of AlN is strongly reduced in submicrometer thin films or devices due to phonon-boundary scattering.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Nov 12, 2019
- Source ID
- 10.1063/1.5097172
Entities
People
- Aditya Sood
- Ankita Katre
- Bozo Vareskic
- Debdeep Jena
- Eric Pop
- Huili Grace Xing
- Kenneth E. Goodson
- Miguel Muñoz Rojo
- Natalio Mingo
- Runjie Lily Xu
- S. M. Islam
Organizations
- Air Force Office of Scientific Research
- Cornell University
- National Science Foundation
- Savitribai Phule Pune University
- Stanford University
- University of Twente