Atomic Vapor Deposition of Strontium Tantalate Films for MIM Applications

Sr-Ta-O thin films were deposited as high-k dielectrics for metal-insulator-metal applications on 200-mm TiN/Si(100) substrates from a single-source Sr[Ta(OEt)₅(methoxyethoxide)]₂ precursor using atomic vapor deposition technique. The variation of process pressure affects the Sr/Ta ratio in the films. Dielectric layers with optimized composition of Sr₂Ta₂O_7-delta possess a capacitance density of 5.5 fF/mum² in combination with a voltage linearity coefficient of 80 ppm/V² and a quality factor of 52 at 10 kHz. The optimized films with thickness of 30 nm exhibit a leakage current density of 7 ldr 10^-9 A/cm² at 2 V and a breakdown strength of 3.2 MV/cm, and, therefore, meet the requirements of the current International Roadmap for Semiconductors.