Thin film deposition of barium strontium titanate by metal organic decomposition technique

With increasing integration density and shrinking geometry DRAM fabrication technology has remained at the forefront of semiconductor industry. The basic unit of a DRAM is a single MOSFET with a storage capacitor. Although dimensions are being reduced there is hardly any room for reduction in the cell capacitance. This calls for methods to improve the charge storage in the miniature devices. The search for high dielectric constant materials has led to the use of ferroelectrics for charge storage. Barium strontium titanate (Ba1-xSrxTiO3) (BST) has thus found a very important place in the fabrication of DRAMs. The metal organic decomposition (MOD) process is a technique for the growth of inorganic films without processing in vacuum or going through a powder step. It is a simple process that is both fast and economical, with very minimal investment. Thin films of BST were deposited on platinized silicon substrates by the spin-on method. The films were then pyrolyzed and annealed. The films obtained were characterized for their compositional and structural properties as well as dielectric constant measurements. This paper presents the method of film preparation and some of the properties of the film.