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 Sr
₂
Ta
₂
O
_7-delta
possess a capacitance density of 5.5 fF/mum
²
in combination with a voltage linearity coefficient of 80 ppm/V
²
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/cm
²
at 2 V and a breakdown strength of 3.2 MV/cm, and, therefore, meet the requirements of the current International Roadmap for Semiconductors.