Thermal conductivity measurements of amorphous HafSO$_x$ and AlPO thin films*

The novel insulators HafSO$_x$ and AlPO are useful as gate dielectrics in field effect transistors as high quality, atomically flat, dense films with low current leakage can be deposited at low temperatures. Since these materials are expected to be used in microelectronics, it is important to understand their thermal transport properties. The room temperature thermal conductivity of thin HafSO$_x$ and AlPO films is determined by a differential 3-omega method, which uses an alternating current signal to heat a sample and a resistance temperature detector (RTD) to measure the frequency- dependent magnitude and phase of the resulting temperature oscillations. The method is modified by using two heater/RTDs of different widths deposited on a single sample to eliminate the need for a reference substrate.