Barium strontium titanate (BST) thin films by erbium donor doping

摘要

A semiconductor device and process for making the same are disclosed which incorporate a relatively large percentage of erbium dopant (1 to 5%) into a BST dielectric film 24 with small grain size (e.g. 10 nm to 50 nm). Dielectric film 24 is preferably disposed between electrodes 18 and 26 (which preferably have a Pt layer contacting the BST) to form a capacitive structure with a relatively high dielectric constant and relatively low leakage current. Apparently, properties of the thin film deposition and small grain size, including temperatures well below bulk BST sintering temperatures, allow the film to support markedly higher defect concentrations without erbium precipitation than are observed for bulk BST. For erbium doping levels generally between 1% and 3%, over an order of magnitude decrease in leakage current (compared to undoped BST) may be achieved for such films.