In situ preparation of high dielectric constant, low-loss ferroelectric BaTiO_3 films on Si at 500℃

摘要

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 1C devices, BaTiO_3 films were prepared on Pt/Ti/(100) Si substrate at 500 ℃ 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 BaTiO_3 films deposited under the conditions of 500 ℃ substrate temperature, 120W target power and 0.3 Pa gas pressure with a 4:1 Ar/O_2 flow ratio displayed good ferroelectric and dielectric properties. The microstructure analysis by XRD and AFM indicated that these BaTiO_3 films were polycrystalline with a preferred (001) orientation and a smooth surface with a Ra ~ 1.7 nm. The twice remnant polarization 2Pr was 10.9 μC/cm~2 @ 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.