In situ preparation of high dielectric constant, low-loss ferroelectric BaTiO3 films on Si at 500 °C

In an attempt to build a CMOS-compatible process with reduced thermal budget for the integration of barium titanate ferroelectric films into Si-based MEMS and IC devices, BaTiO3 films were prepared on Pt/Ti/(1 0 0) Si substrate at 500 °C by a rf magnetron sputtering process without a post-growth annealing. Effects of substrate temperature, gas composition, gas pressure and target power on the microstructure of these films were analyzed in details. The BaTiO3 films deposited under the conditions of 500 °C substrate temperature, 120 W target power and 0.3 Pa gas pressure with a 4:1 Ar/O2 flow ratio displayed good ferroelectric and dielectric properties. The microstructure analysis by XRD and AFM indicated that these BaTiO3 films were polycrystalline with a preferred (0 0 1) orientation and a smooth surface with a Ra ∼ 1.7 nm. The twice remnant polarization 2Pr was 10.9 μC/cm2 @ 1 kHz, while the relative dielectric constant and dielectric loss tangent were measured to be 720/0.042 @ 1 kHz, and 360/0.038 @ 1 MHz, respectively.