Thermal conductivity of plasma-enhanced atomic layer deposited hafnium zirconium oxide dielectric thin films

Hafnium zirconium oxide (HZO) is promising for applications in future memory devices and energy storage and harvesting. While many studies have focused upon the dielectric and structural properties of HZO, much less investigated are their thermal properties, particularly in thin-film form. We present the first report on the thermal conductivity of plasma-enhanced atomic layer deposited (PEALD) HZO thin films. Steady-state thermoreflectance measures the effective thermal conductivity of undoped and yttrium-doped HZO films and their interfaces. The effective thermal conductivity of the undoped film is found to be 0.75 W m^–1 K^–1, which is comparable to those reported previously for thermal ALD HZO films with similar composition. With increasing yttrium doping level, the effective thermal conductivity slightly decreases down to 0.67 W m^–1 K^–1 owing to dopant scattering of phonons. Our PEALD HZO films are nanocrystalline as observed by grazing-incidence X-ray diffraction and transmission electron microscopy.