The Effects of the Precursor Solutions on the Structure and the Properties of Sol-Gel Derived BST Thin Films

초록

We have studied the effects of solvents and additives in the precursor solutions on the characteristics of barium strontium titanate (BST) thin films. The solution having two solvents, i.e. acetic acid for barium acetate and strontium acetate and 2-methoxyethanol for titanium isopropoxide and also having an addtive of ethylene glycol shows good stability and remains homogeneous even after a month of ageing. It produces excellent BST thin film without cracks. Dielectric constant, loss tangent at 10kHz and leakage current density at 3V of the BST(70/30) thin film made from this solution are 339, 0.052 and 13.3uA/cm2, respectively. We have aslo found that a Ta layer is a better diffusion barrier aginst Si than a Ti layer and is functional up to 750C