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

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 O ₂-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.