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Effects of Post-Annealing Temperatures and Ambient Atmospheres on the Electrical Properties of Ultrathin (Ba,Sr)TiO 3 Capacitors

1998; Institute of Physics; Volume: 37; Issue: 9S Linguagem: Inglês

10.1143/jjap.37.5112

1347-4065

Po-ching Chen Po-ching Chen, Hiroshi Miki, Y. Shimamotο, Yuichi Matsui Yuichi Matsui, Masahiko Hiratani, Yoshihisa Fujisaki,

Semiconductor materials and devices

Ultrathin (Ba,Sr)TiO 3 (BST) film capacitors with a Pt/Ba 0.5 Sr 0.5 TiO 3 (30 nm)/Pt/TiN/Si structure were fabricated. To investigate the effects of annealing temperatures, capacitors were annealed in flowing Ar or O 2 at temperatures ranging from 400°C to 600°C for 30 min. The electrical properties of the annealed samples were strongly dependent on the annealing temperatures. In the capacitors annealed at 500°C (in Ar and O 2 ) and 550°C (in O 2 ), the leakage current decreased to a level of 10 -8 A/cm 2 when the bias voltage was ±1.5 V. In the as-deposited sample, the maximum capacitance appeared at a bias voltage of -1 V. However, the maximum capacitance increased and appeared at the zero bias voltage after annealing. These phenomena are believed to be defect-related (due to oxygen vacancies). The annealing atmospheres were also found to have an effect on preserving the morphology of the Pt electrodes.