Using Mosaicity to Tune Thermal Transport in Polycrystalline AlN Thin Films
Type
ArticleAuthors
Singh, ShivkantShervin, Shahab
Sun, Haiding

Yarali, Milad
Chen, Jie
Lin, Ronghui

Li, Kuang-Hui
Li, Xiaohang

Ryou, Jae-Hyun
Mavrokefalos, Anastassios
KAUST Department
Advanced Semiconductor LaboratoryComputer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division
Electrical Engineering Program
Material Science and Engineering Program
Physical Science and Engineering (PSE) Division
Date
2018-05-17Online Publication Date
2018-05-17Print Publication Date
2018-06-13Permanent link to this record
http://hdl.handle.net/10754/627942
Metadata
Show full item recordAbstract
The effect of controlling the c-axis alignment (mosaicity) to the cross-plane thermal transport in textured polycrystalline aluminum nitride (AlN) thin films is experimentally and theoretically investigated. We show that by controlling the sputtering conditions we are able to deposit AlN thin films with varying c-axis grain tilt (mosaicity) from 10° to 0°. Microstructural characterization shows that the films are nearly identical in thickness and grain size, and the difference in mosaicity alters the grain interface quality. This has a significant effect to thermal transport where a thermal conductivity of 4.22 W/mK vs. 8.09 W/mK are measured for samples with tilt angles of 10° vs. 0° respectively. The modified Callaway model was used to fit the theoretical curves to the experimental results using various phonon scattering mechanisms at the grain interface. It was found that using a non-gray model gives an overview of the phonon scattering at the grain boundaries, whereas treating the grain boundary as an array of dislocation lines with varying angle relative to the heat flow, best describes the mechanism of the thermal transport. Lastly, our results show that controlling the quality of the grain interface provides a tuning knob to control thermal transport in polycrystalline materials.Citation
Singh S, Shervin S, Sun H, Yarali M, Chen J, et al. (2018) Using Mosaicity to Tune Thermal Transport in Polycrystalline AlN Thin Films. ACS Applied Materials & Interfaces. Available: http://dx.doi.org/10.1021/acsami.8b02899.Sponsors
A. M. acknowledges financial support from the University of Houston. J.H.R. acknowledges partial support from the Texas Center for Superconductivity at the University of Houston (TcSUH).Publisher
American Chemical Society (ACS)Additional Links
https://pubs.acs.org/doi/10.1021/acsami.8b02899ae974a485f413a2113503eed53cd6c53
10.1021/acsami.8b02899