High Temperature Thermal Conductivity of Amorphous Al2O3 Thin Films Grown by Low Temperature ALD


  • This research receives funding from the “Laboratoire National de Métrologie at d'Essais”, from the European Union on the basis of Decision No. 912/2009/EC, and was partially supported by “MONADS” Project (code No. 2009–2715) of the Cariplo Foundation. The authors thank Dr. Luca Lamagna from MDM for depositing the Al2O3 layers and Dr. Yannick Anguy from I2M for the ESEM measurements.


Al2O3 grown by atomic layer deposition could be proposed as a nonactive layer for back end processes in view of the integration of scaled phase change memory devices. In this paper we report on thermal characterization from 50 to 600 °C of amorphous Al2O3 thin films grown on thermally oxidized silicon substrate at a temperature of 100 °C and capped with a 30 nm thick Pt layer. The effects of low temperature deposition and of a post-deposition rapid thermal annealing process (RTP) on the thermal properties of the films are investigated using a modulated photo-thermal radiometry technique coupled with post-annealing morphological characterizations. Degassing process occurring at high temperature greatly affects the film surface quality, though measurements of the films after RTP show that the thermal conductivity of amorphous Al2O3 increases as a function of temperature from 1.8 W K−1 m−1 at 50 °C to 3.3 W K−1 m−1 at 600 °C. At the same time, the value of the thermal boundary resistance at the Pt-Al2O3 interface decreases from 1.02 × 10−7 K m2 W−1 at 50°C to 4.8 × 10−8 K m2 W−1 at 600 °C.