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Title: Static ferroelectric memory transistor having improved data retention

An improved ferroelectric FET structure in which the ferroelectric layer is doped to reduce retention loss. A ferroelectric FET according to the present invention includes a semiconductor layer having first and second contacts thereon, the first and second contacts being separated from one another. The ferroelectric FET also includes a bottom electrode and a ferroelectric layer which is sandwiched between the semiconductor layer and the bottom electrode. The ferroelectric layer is constructed from a perovskite structure of the chemical composition ABO.sub.3 wherein the B site comprises first and second elements and a dopant element that has an oxidation state greater than +4 in sufficient concentration to impede shifts in the resistance measured between the first and second contacts with time. The ferroelectric FET structure preferably comprises Pb in the A-site. The first and second elements are preferably Zr and Ti, respectively. The preferred B-site dopants are Niobium, Tantalum, and Tungsten at concentrations between 1% and 8%.
Inventors:
 [1];  [2];  [3]
  1. (13609 Verbena Pl., N.E., Albuquerque, NM 87112)
  2. (7716 Wm. Moyers Ave., NE., Albuquerque, NM 87112)
  3. (12808 Lillian Pl., NE., Albuquerque, NM 87112)
Issue Date:
OSTI Identifier:
870703
Assignee:
Evans, Jr., Joseph T. (13609 Verbena Pl., N.E., Albuquerque, NM 87112);Warren, William L. (7716 Wm. Moyers Ave., NE., Albuquerque, NM 87112);Tuttle, Bruce A. (12808 Lillian Pl., NE., Albuquerque, NM 87112) SNL
Patent Number(s):
US 5578846
Contract Number:
AC04-76
Research Org:
Sandia National Laboratories (SNL), Albuquerque, NM, and Livermore, CA
Country of Publication:
United States
Language:
English
Subject:
static; ferroelectric; memory; transistor; improved; data; retention; fet; structure; layer; doped; reduce; loss; according; semiconductor; contacts; thereon; separated; bottom; electrode; sandwiched; constructed; perovskite; chemical; composition; site; comprises; elements; dopant; element; oxidation; sufficient; concentration; impede; shifts; resistance; measured; time; preferably; pb; a-site; zr; respectively; preferred; b-site; dopants; niobium; tantalum; tungsten; concentrations; perovskite structure; chemical composition; semiconductor layer; preferably comprises; resistance measured; sufficient concentration; structure preferably; ferroelectric layer; ferroelectric memory; ferroelectric fet; bottom electrode; dopant element; improved data; improved ferroelectric; memory transistor; site comprises; preferably comprise; /257/