Low Temperature Low Temperature Processing of Dielectric Processing of Dielectric Thin Films Thin Films Chris Bratten Chris Bratten Advisors Advisors Prof. E. Slamovich Prof. E. Slamovich Prof. H. Hillhouse Prof. H. Hillhouse
Dec 22, 2015
Low Temperature Processing Low Temperature Processing of Dielectric Thin Filmsof Dielectric Thin Films
Low Temperature Processing Low Temperature Processing of Dielectric Thin Filmsof Dielectric Thin Films
Chris BrattenChris Bratten
AdvisorsAdvisorsProf. E. SlamovichProf. E. SlamovichProf. H. HillhouseProf. H. Hillhouse
Chris BrattenChris Bratten
AdvisorsAdvisorsProf. E. SlamovichProf. E. SlamovichProf. H. HillhouseProf. H. Hillhouse
Research GoalsResearch GoalsResearch GoalsResearch Goals
Produce thin films of Barium Titanate using Produce thin films of Barium Titanate using hydrothermal synthesishydrothermal synthesis
Verify formation of BaTiOVerify formation of BaTiO33 on substrates using on substrates using x-ray diffractionx-ray diffraction
Determine the dielectric properties of the films Determine the dielectric properties of the films producedproduced
ProcessProcessProcessProcess
Used ½ length glass slides as substratesUsed ½ length glass slides as substrates Cleaned slides using TCA, acetone and Cleaned slides using TCA, acetone and
methanolmethanol Sputtered 2 platinum electrodesSputtered 2 platinum electrodes Deposited a thin film of titanium onto the slides Deposited a thin film of titanium onto the slides
by evaporation to connect the 2 Pt electrodesby evaporation to connect the 2 Pt electrodes
Process Process (cont)(cont)Process Process (cont)(cont)
Samples immersed in Samples immersed in solutionsolution
– 125mL PE bottle125mL PE bottle
– 11MM BaCl BaCl2 2 + NaOH+ NaOH
– 11MM Ba(OH) Ba(OH)22
““Baked” at Baked” at temperatures between temperatures between 60 and 9060 and 90ooC for about 24 C for about 24 hours or morehours or more
Process Process (cont)(cont)Process Process (cont)(cont)
Samples removed from solution in a nitrogen Samples removed from solution in a nitrogen atmosphere (glove box)atmosphere (glove box)
Avoid formation of barium carbonateAvoid formation of barium carbonate Rinsed in a ph=12 solution then placed in Rinsed in a ph=12 solution then placed in
ethanolethanol– Solutions kept warm in ovenSolutions kept warm in oven– Samples taken out of glove box while immersed in Samples taken out of glove box while immersed in
ethanolethanol Samples removed from ethanol and blown dry Samples removed from ethanol and blown dry
with airwith air
ProblemsProblemsProblemsProblems
Film adhesionFilm adhesion– Platinum being stripped Platinum being stripped
from slide in solutionfrom slide in solution
– Same for titanium, but Same for titanium, but not as much over not as much over platinumplatinum
Barium CarbonateBarium Carbonate– ContaminantContaminant
– Result of reaction with Result of reaction with carbon dioxide in air or carbon dioxide in air or solutionsolution
ChangesChangesChangesChanges
Switched solutionSwitched solution– 11MM Ba(OH) Ba(OH)22
– Better results, visuallyBetter results, visually
– Still had film loss in solution, but not as much as Still had film loss in solution, but not as much as beforebefore
Stopped depositing platinumStopped depositing platinum– Mostly lost in solutionMostly lost in solution
– Getting rid of an extra stepGetting rid of an extra step
Capacitance TestingCapacitance TestingCapacitance TestingCapacitance Testing
Tested the 3 best samples based on XRD Tested the 3 best samples based on XRD informationinformation
Used TEM grids as a mask and deposited Used TEM grids as a mask and deposited titanium over the sampletitanium over the sample
Created a grid of electrodesCreated a grid of electrodes Used a LCR meter and probes to test Used a LCR meter and probes to test
capacitance of film between electrodescapacitance of film between electrodes
Capacitance TestingCapacitance TestingCapacitance TestingCapacitance Testing
Sample 10 - Site 3
14.4
14.6
14.8
15.0
15.2
15.4
15.6
15.8
16.0
-600 -400 -200 0 200 400 600
Distance From Origin (micrometers)
Me
as
ure
d
Ca
pa
cit
an
ce
(p
F)
x-axisy-axis
Minimum Recorded Value: 14.015 pFAverage Recorded Value: 15.130 pFMaximum Recorded Value: 15.876 pF
Capacitance TestingCapacitance TestingCapacitance TestingCapacitance Testing
Sample 14 - Site 2
20
25
30
35
40
45
50
0 100 200 300 400 500 600 700 800 900 1000 1100
Distance From Origin (micrometers)
Mea
sure
d C
apac
itan
ce (
pF
)
x-axisy-axis
Minimum Recorded Value: 34.58 pFAverage Recorded Value: 40.59 pFMaximum Recorded Value: 64.90 pF
Capacitance TestingCapacitance TestingCapacitance TestingCapacitance Testing
Sample 17 - Site 1
0
50
100
150
200
250
300
0 200 400 600 800 1000 1200 1400 1600
Distance From Origin (micrometers)
Me
as
ure
d C
ap
ac
ita
nc
e
(pF
)
x-axisy-axis
Minimum Recorded Value: 122.2 pFAverage Recorded Value: 175.7 pFMaximum Recorded Value: 284.2 pF
Capacitance and TemperatureCapacitance and TemperatureCapacitance and TemperatureCapacitance and Temperature
76
78
80
82
84
86
88
90
92
0 50 100 150 200 250 300Measured Capacitance (pF)
Tem
per
atu
re (
deg
rees
C)
Sample 10
Sample 14
Sample 17
Dielectrics and TemperatureDielectrics and TemperatureDielectrics and TemperatureDielectrics and Temperature
76
78
80
82
84
86
88
90
92
0 20 40 60 80 100 120 140 160 180Maximum Calculated r
Te
mp
era
ture
(d
eg
ree
s C
)
Sample 10Sample 14Sample 17
ConclusionsConclusionsConclusionsConclusions
Film qualities with relation to temperatureFilm qualities with relation to temperature– Based on XRD data:Based on XRD data:
Higher Temperatures lead to more BaTiOHigher Temperatures lead to more BaTiO33
– Based on LCR data:Based on LCR data: Too close to callToo close to call
– Generally, a higher temperature will produce a Generally, a higher temperature will produce a better filmbetter film
Fresh solutions lead to better filmsFresh solutions lead to better films Solutions “baked” for more than 24 hours Solutions “baked” for more than 24 hours
showed no major advantage over othersshowed no major advantage over others
Thanks To…Thanks To…Thanks To…Thanks To…
Prof. SlamovichProf. SlamovichProf. HilhouseProf. Hilhouse
MSEE DepartmentMSEE DepartmentPurdue UniversityPurdue University
My Fellow REU StudentsMy Fellow REU Students