Thermal Conductivity of Nano-Crystallized Indium-Gallium-Zinc Oxide Thin Films Determined by Differential Three-Omega Method

The temperature dependence thermal conductivity of the indium-gallium-zinc oxide (IGZO) thin films was investigated with the differential three-omega method for the clear demonstration of nanocrystallinity. The thin films were deposited on an alumina (α-Al2O3) substrate by direct current (DC) magnetron sputtering at different oxygen partial pressures ([PO2] = 0%, 10%, and 65%). Their thermal conductivities at room temperature were measured to be 1.65, 1.76, and 2.58 Wm−1K−1, respectively. The thermal conductivities decreased with an increase in the ambient measurement temperature. This thermal property is similar to that of crystalline materials. Electron microscopy observations revealed the presence of nanocrystals embedded in the amorphous matrix of the IGZO films. The typical size of the nanocrystals was approximately 2–5 nm with the lattice distance of about 0.24–0.26 nm. These experimental results indicate that the nanocrystalline microstructure controls the heat conduction in the IGZO films.

Measurement of the Thermal Conductivity of Polydimethylsiloxane Polymer Using the Three Omega Method

Polydimethylsiloxane (PDMS) has widely appeared in different electronic and medical applications. The knowledge of the thermal properties of PDMS and especially its thermal conductivity is required while processing PDMS to design a particular device. In this paper measurement of the thermal conductivity of PDMS using the three omega method is presented at different temperatures. The three omega method has been chosen because of its ease of use and accuracy. It requires the fabrication of metallic lines which act as heaters and thermometers on the surface of the material under test. A different procedure is introduced in this paper through which the metallic lines are embedded in the surface of PDMS. Experimental results are then compared to Cahill's approximate solution and to the results obtained by numerical simulations using a finite element method.