Analysis of RF-sputtered BaTiO3 thin film capacitors with Ni electrodes using a statistical design of experiments: Part 2 - DC Analysis

Investigation of nanoscale BaTiO3 thin film capacitors with Ni electrodes
deposited by RF-magnetron sputtering using design of experiments and DC test methods was conducted. The devices were approximately 125 nm thick BaTiO3 sputtered under varying RF powers (100-200 W), plasma compositions (10%-50% O2 balance Ar), and deposition temperatures (20°C to 300°C) with approximately 25 nm thick Ni electrodes. Current voltage (I-V) plots indicated highly insulating films with resistances at 1 V between 16 and 270 GΩ. Hysteresis loops indicated a mix of paraelectric and ferroelectric films depending on the deposition conditions, with permittivities ranging from 170 to 10,000. Electrical testing at temperatures between 25°C and 300°C showed increasing conductivity as the temperature increased with activation energies ranging from 0.3 to 0.9 eV for conduction, along with limited amounts of remnant ferroelectric behavior. Statistical analysis of the data resulted in mathematical surface response
models with R2 values of 0.90 to 0.99, but complex higher order interactions resulted in the models incorrectly estimating the predicted values.