Ba1-xSrxTiO3 (BST) is a leading candidate as a new dielectric material for capacitors in the future generations of ultra-large-scale integrated dynamic random access memories. However, for MOCVD processes, the deposition temperatures of BST films are on the range of 800°C, and the deposition rate is still low. Specially, it is difficult to deposit high quality nanoscale thin films on large diameter wafers. To solve these problems, EMCORE has developed an advanced oxide MOCVD tool and one and two step plasma enhanced MOCVD techniques to deposit BST thin films. The experimental results show that using this tool and two step PE-MOCVD techniques, high quality BST thin films can be successfully deposited on large area substrates. Typically, the 200 nm thick Ba 0.5Sr0.5TiO3 thin films on Pt electrodes have a dielectric constant around 600, and a leakage current of less than 2.0 × 10-7A/cm2 at 100KV/cm and room temperature. These characteristics suggest that the PE-MOCVD and two step process techniques can be used in the manufacturing of reliable, high density memory devices. In addition, the relationship between composition, microstructure and the electrical properties of the BST thin films was also investigated.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Control and Systems Engineering
- Ceramics and Composites
- Condensed Matter Physics
- Electrical and Electronic Engineering
- Materials Chemistry