Ferroelectric field effect transistors for nonvolatile memory applications having functional gradient material
US6236076A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Apr 29, 1999 |
| Grant date | May 22, 2001 |
| Priority date | — |
| Expiry date | Apr 29, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D1/684
Abstract
A nonvolatile nondestructible read-out ferroelectric FET memory comprising a semiconductor substrate, a ferroelectric functional gradient material ("FGM") thin film, and a gate electrode. In one basic embodiment, the ferroelectric FGM thin film contains a ferroelectric compound and a dielectric compound. The dielectric compound has a lower dielectric constant than the ferroelectric compound. There is a concentration gradient of the ferroelectric compound in the thin film. In a second basic embodiment, the FGM thin film is a functional gradient ferroelectric ("FGF"), in which compositional gradients of ferroelectric compounds result in unconventional hysteresis behavior. The unconventional hysteresis behavior of FGF thin films is elated to an enlarged memory window in ferroelectric FET memories. FGM thin films are preferably formed using a liquid source MOD methods, preferably a multisource CVD method.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.