[Back]

V. Moraes, H. Riedl, H. Bolvardi, S. Koloszvári, M. Ikeda, L. Prochaska, S. Paschen, P.H. Mayrhofer:
"Thermal Conductivity and Mechanical Properties of AlN-based Thin Films";
Talk: AVS 63rd Symposium & Exhibition, Nashville, TN, USA; 2016-11-06 - 2016-11-11; in: "AVS 63rd International Symposium & Exhibition", 225304 (2016), 1 - 10.

While many research activities concentrate on mechanical properties and thermal stabilities of protective thin films,
only little is known about their thermal properties being essential for the thermal management in various industrial
applications. Based on the 3ω-method, we show the influence of Al and Cr on the temperature dependent thermal
conductivity of single-phase cubic structured TiN and single-phase wurtzite structured AlN thin films, respectively,
and compare them with the results obtained for CrN thin films.
The dc sputtered AlN thin films revealed a highly c-axis oriented growth for deposition temperatures of 250 to 700
°C. Their thermal conductivity was found to increase strongly with the film thickness, indicating progressing
crystallization of the interface near amorphous regions during the sputtering process. For the 940 nm AlN film, we
found a lower boundary for the thermal conductivity of 55.3 W·m-1·K-1. By the substitution of only 10 at.% Al with
Cr, κ significantly reduces to ~ 5.0 W·m-1·K-1, although the single-phase wurtzite structure is maintained. The
single-phase face centered cubic TiN and Ti0.36Al0.64N thin films exhibit at room temperatures κ values of 3.1 W·m-
1·K-1 and 2.5 W·m-1·K-1, respectively. Hence, also here, the substitutional alloying reduces the thermal conductivity,
although at a significantly lower level. Single-phase face centered cubic CrN thin films show κ values of 3.6 W·m-
1·K-1.
For all nitride based thin films investigated, the thermal conductivity slightly increases with increasing temperature
between 200 and 330 K. This rather unusual behavior is based on the high defect density (especially point defects)
within the films prepared by physical vapor deposition.

Thermal conductivity; Nitride based thin films; Alloying effects; 3ω-method;

http://dx.doi.org/10.1063/1.4953358