Effects of Radiation on High-κ Dielectric Materials
Jeffrey Klenzing
NIST-JPL
July 18, 2003
Introduction
Jeffrey Klenzing
University of Texas at
Dallas
Graduation – May ‘04
Working with
Dr. John Suehle
AIP
American Institute of
Physics
2003 SPS-AIP
National Internship
Program
Outline
SiO2: Pushing the Limits
Why SiO2 must be
replaced
JPL
Why the Jet Propulsion
Laboratory is interested
Experiment
What we are doing
Preliminary Results
What we have done and
where to go from here
SiO2: Pushing the Limits
Demands for increased performance of
electronic devices have skyrocketed
over the last few years.
Cell-phones, PDA’s, digital cameras,
digital video, and many combinations
of the above as well.
Thin Oxide
Gate
Silicon Substrate
B. Weir, et al, IEDM 1997, p.73
Leff
Ids= Cox (Vgs-Vth)2
L2
Cox= εA/tox
Must keep Cox constant to maintain channel current (Ids).
2.4 nm
SiO2: Pushing the Limits
SiO2: Pushing the Limits
Increased
performance relies
on making the gate
oxide thinner.
Theoretically, higher
κ would mean that a
thicker film could be
used.
Cox = εA/tox
where
ε = ε0 κ
SiO2 has κ = 3.9
HfO2 has κ ~ 20-30
JPL: Deep Space Probes
Space is not the best
place for electronics:
Radiation
High-energy
particles
Repair service to the
outer reaches of the
solar system can be
a problem.
JPL: Intel Inside
Most of NASA’s
electronics are off-the-
shelf.
Well characterized for
Radiation
Durability
Currently controlled
by the 386 chip.
Picture obtained from http://www.qsl.net/dg7ro/iss/picture.htm
Proposed Experiment
Determine
reliability of
high-κ dielectrics
as a function of
Total Ionizing
Dose (TID)
Initial
Measurements
Irradiation
Measure
Compare
Experiment: The Devices
Produced by
International Sematech,
Inc.
CVD TiN Gate
Monolayers of HfO2 and
Al2O3
Si Substrate
Experiment: The Devices
Wafer 03 Wafer 13 Wafer 17
Ratio of HfO2
to Al2O3
1:1
5:1
1:0
EOT* (Å)
19.8
23.57
15.19
* EOT = Equivalent SiO2 Thickness
Experiment: The La