Physical and electrical properties of ZrO2 and YSZ high-k gate dielectric thin films grown by RF magnetron sputtering

Abstract

Thin films of ZrO2 were deposited on p-Si(100) substrates using RF magnetron sputtering technique. To investigate the influence of the sputtering parameters, e.g., annealing temperature, different O2-flux, RF power and target to substrate distance on the physical and electrical properties of the as-grown films, systematic investigation using X-ray diffraction (XRD), Fourier transform infrared (FT-IR), scanning electron microscope and energy dispersive X-ray (SEM–EDX), C–V, and I–V were carried out in this work. Deposited ZrO2 films had polycrystalline after annealing sample at high temperature. Their silicon oxide (SiO2) layers were formed between high-k film (i.e., ZrO2 and YSZ) and Si substrate either after annealing samples at high temperature or introducing O2-flux the sputtering process step. The high-k thin films have to be deposited amorphous structure without SiO2 interlayers. We also investigated the electrical properties of both the a-ZrO2 and a-YSZ films prepared without O2-flux at room temperature with conditions of various RF power and target to substrate distance. The dielectric constant of amorphous YSZ was determined to be about 24 using metal–insulator–semiconductor (MIS) capacitor structure. The smallest leakage current density of the YSZ film grown at 150 W and at room temperature was obtained to be about 10−10 at 1 V.