Barium strontium titanate (BST) thin films by holmium donor doping
US5453908A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 30, 1994 |
| Grant date | Sep 26, 1995 |
| Priority date | — |
| Expiry date | Sep 30, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D1/684
Abstract
A semiconductor device and process for making the same are disclosed which incorporate a relatively large percentage of holmium dopant (0.5 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 holmium precipitation than are observed for bulk BST. For holmium doping levels generally between 0.5 and 5% (compensated with titanium and/or manganese), better than 50% improvement in dielectric constant and two to six orders of magnitude reduction in leakage current (compared to undoped BST) have been observed for such films.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.