Dielectric properties enhancement of ZrO2 thin films induced by substrate biasing

We have fabricated zirconia (ZrO2) thin films on Si (100) wafers that possess excellent dielectric properties such as high permittivity up to 53 and excellent frequency stability. The good performance is mainly attributed to the improvement in the crystallinity and orientation of the thin films and the interfacial structure using substrate biasing. The bias endues positive ions with high energy and diffusion of the incident particles and relaxation of the surface are enhanced by collisions between the impinging positive ions accelerated through the plasma sheath and substrate atoms. In addition, the higher nuclei density on the surface as a result of substrate biasing is beneficial to the fabrication of oriented thin films and the dielectric properties of the thin films are improved as the substrate bias goes up. The results increase our understanding of the factors leading to the deposition of high-quality ZrO2 dielectric thin films that are able to meet the requirements for capacitors in next-generation memory devices.