Passivation properties of HfO2-SiO2 mixed metal oxide thin films with low reflectivity on silicon substrates for semiconductor devices

HfO2-SiO2 mixed oxide-based thin films were introduced in this work, and their passivation and anti-reflection properties were examined by using carrier lifetime, x-ray diffraction, scanning electron microscope, energy dispersive x-ray analysis, reflectance, and Fourier transform infrared measurements. The HfO2-SiO2 mixed oxide solutions were prepared with different composition ratios, and the thin films were formed on p-type CZ-Si substrates using the spin-coating technique. Annealing of the samples was carried out in ambient air at different temperatures after optimizing the solution ratio. When annealed at 600 and 700 degrees C, the average reflectance of the samples was observed to be around 15% in the spectral range of 300-1000 nm, with a minimum reflectance point lying in the visible range. The effective carrier lifetimes increased up to 32 mu s after annealing at 600 degrees C compared to the initial lifetime of around 2 mu s. Annealing at higher temperatures significantly decreased the carrier lifetimes (4.5 and 0.6 mu s for 700 and 800 degrees C, respectively). The results of this study revealed that the HfO2-SiO2 mixed oxide films can provide a good passivation effect in addition to an effective antireflection property depending on the annealing temperature.