Static ferroelectric memory transistor having improved data retention

Patent · Mon Jan 01 00:00:00 EST 1996

OSTI ID:870703

Warren, William L ^[1]; Tuttle, Bruce A ^[2]

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1. 7716 Wm. Moyers Ave., NE., Albuquerque, NM 87112
2. 12808 Lillian Pl., NE., Albuquerque, NM 87112

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%.

• Research Organization: Sandia National Laboratories (SNL), Albuquerque, NM, and Livermore, CA (United States)
• DOE Contract Number: AC04-76
• 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)
• Patent Number(s): US 5578846
• OSTI ID: 870703
• Country of Publication: United States
• Language: English

Related Subjects

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
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