Transcript Title

Thin-Film Inorganic HighPerformance Devices via Additive
Processing
4/5/2005
Inorganic Devices via Additive Processing
Thin-Film Inorganic High-Performance
Devices via Additive Processing
Semiannual Review, April 2005
Chemistry – Jeremy Anderson, Stephen Meyers,
Jason Stowers, Douglas Keszler
Electrical Engineering – David Hong, John Olson,
Hai Chiang, John F. Wager
Chemical Engineering – Yu-jen Chang, Alex
Chang
July 6, 2015
2
Inorganic Devices via Additive Processing
Goals:
• Demonstrate low-temperature fabrication (T < 100oC)
• Achieve high performance in transistor mobility
(μINC  50 cm2/Vs)
• Complementary n- and p-type behavior in solution
processed semiconductors
July 6, 2015
3
Inorganic Devices via Additive Processing
Process:
• Materials identification and invention
• Literature precedents, physical and chemical
models
• Physical vapor deposition of thin films
• Chemical process development
• Single-source precursors
• Nanolaminates
• Printing
• Device characterization and development
• Transistors and capacitors
July 6, 2015
4
Inorganic Devices via Additive Processing
Results:
• Enhanced performance in HafSOx dielectric
• New low-K phosphate dielectric
• New single-source precursor for near roomtemperature deposition of ZnO
• Nanolaminates for toolbox approach to
multicomponent materials and control of function
• Use of nonaqueous solutions for ink-jet printing
• Solution processed transistor (dielectric + channel)
• Materials/Process Studies: Physical vapor
deposition of new oxide transistors and p-type
5
oxides
July 6, 2015
Solution-Based Deposition
Jeremy Anderson
Stephen Meyers
Jon Olson
Outline Solution Processed Films
1.
Special considerations solution processing
2.
Presentation four materials systems
3.
Electrical characterization four materials
systems
July 6, 2015
July 6, 2015
July 6, 2015
77
HP Confidential
77
GSH, page 7
Conversion liquid film to solid film
L
M
polymerization
L
H
OH
L
H
M
M
O
M
M
L
L
M
M
O M
M
O
L
O
M
M
O
M
O
M
O
M
July 6, 2015
combustion
O
O
H
M
M
M
L
L
O
M
O
M
O
O M
O
M
O
M
M
O
M
8
Strategy:
Rapid Low Temperature Reaction
•
Dense film formation requires extended bond
formation
•
Polymerization process should have low
activation energy
July 6, 2015
July 6, 2015
July 6, 2015
99
HP Confidential
99
GSH, page 9
Hydrated oxides
-complete layer mixingoxide #1
oxide #2
anneal
ternary oxide
July 6, 2015
10
Hydrated oxide
-no layer mixingoxide #1
oxide #2
anneal
July 6, 2015
11
Update for dielectric Hafsox
•
Hafsox/La developed as “next generation”
Hafsox
1) Films contain lower content of chlorine and
water than Hafsox
2) Greater reliability than Hafsox
3) More “ideal” behavior as gate dielectric
(compared to Hafsox)
•
Zircsox made as zirconium analog of Hafsox
July 6, 2015
July 6, 2015
July 6, 2015
12
12
12
12
HP Confidential
GSH, page 12
Rapid Low Temperature Reaction: Hafsox/La
Reaction Hafsox
HfOCl2 + x H2SO4 + (1-x) H2O 325º C
HfO2-x(SO4)x + 2 HCl
Reaction Hafsox/La
325º C
HfOCl2 + x La2(SO4)3 + H2O
HfLa2xO2(SO4)3x + 2HCl
July 6, 2015
July 6, 2015
July 6, 2015
13
13
13
13
HP Confidential
GSH, page 13
Demonstration of smooth
reproducible thin layers
Hafsox HfO2-x(SO4)x
Zircsox ZrO2-x(SO4)x
substrate
Film thickness demonstrated at 5 nm.
July 6, 2015
14
X-ray reflectivity for Hafsox/Zircsox
multilayer film
8
Bragg reflections
log (cps)
6
4
2
0
0
July 6, 2015
July 6, 2015
July 6, 2015
2
4
6
2 theta
HP Confidential
8
10
15
15
15
15
GSH, page 15
Rapid Low Temperature Reaction:
Tin oxide phosphate (TOP)
600ºC
SnCl4 + H2O2 + 2H2O
SnO2 + O2 + 4HCl
moderate polymerization
500ºC
SnCl4 + 0.2 H3PO4 + 1.7 H2O
SnO1.7(PO4)0.2 + 4HCl
improved polymerization
July 6, 2015
July 6, 2015
July 6, 2015
16
16
16
16
HP Confidential
GSH, page 16
Rapid Low Temperature Reaction: ZnO
Limitations of Past Approaches
High processing temperatures, poor performance and
non-ideal behavior caused by:
• Residual spectator ions (Halides, Nitrates, Etc.)
• Combustion products (Organics)
→ Grain boundaries
→ Film defects due to material loss
July 6, 2015
July 6, 2015
July 6, 2015
17
17
17
17
HP Confidential
GSH, page 17
Rapid Low Temperature Reaction: ZnO
Precursor:
ZnCl2(aq) + 2NH3(aq) + 2H2O → Zn(OH)2(s) + 2NH4Cl(aq)
Centrifuge and Rinse
Zn(OH)2(s) + xNH3(aq) ↔ Zn(OH)2(NH3)x(aq)
Conversion
Zn(OH)2(NH3)x(aq) → ZnO(s) + xNH3(g) + H2O(g)
300º C
pH
-1
1
July 6, 2015
July 6, 2015
July 6, 2015
3
Zn+ (aq)
5
7
9
11
Zn(OH)2(s)
HP Confidential
13
15
-2
Zn(OH)4 (aq)
18
18
18
18
GSH, page 18
Rapid Low Temperature Reaction: ZnO
Results
•Polycrystalline ZnO films
Rms Roughness ~ 45Å
(25μm2)
• Transistor behavior ≤ 300°C
• Mild deposition conditions
• Direct deposition of metal
oxo-hydroxide
•Low mobility/current density
July 6, 2015
July 6, 2015
July 6, 2015
19
19
19
19
HP Confidential
GSH, page 19
Rapid Low Temperature Reaction:
Aluminum Oxide Phosphate (AlOP)
Al2O3 Corundum
July 6, 2015
July 6, 2015
July 6, 2015
AlPO4 Berlinite
HP Confidential
20
20
20
20
GSH, page 20
Rapid Low Temperature Reaction:
AlOP
Precursor
Al(OH)3(s) + 2HCl(aq) + ½H3PO4(aq)
95º C
Al(OH)Cl2(aq) + ½H3PO4(aq) +2H2O
Polymerization
Al(OH)Cl2(aq) + ½H3PO4(aq)
275º C
AlO3/4(PO4)1/2(s) + 2HCl (g) + ¼H2O
July 6, 2015
July 6, 2015
July 6, 2015
21
21
21
21
HP Confidential
GSH, page 21
Rapid Low Temperature Reaction:
AlOP
Results
• Amorphous AlO3/4(PO4)1/2 dielectric films
• Rms roughness 2.2Å (25 μm2)
• Low temperature dehydration (275º C)
• Highly uniform dielectric properties
• Mechanically robust films
• Deposition pH 3-4
July 6, 2015
July 6, 2015
July 6, 2015
22
22
22
22
HP Confidential
GSH, page 22
Rapid Low Temperature Reactions:
Chemical Implications
•Aluminum Oxide Phosphate:
Widely applicable chemistry - Building a “Tool Box”
•Tin Oxide Phosphate:
Seeking intelligent deposition routes
•Zinc Oxide:
Direct chemical deposition of the desired material
•Hafsox/La:
Functional gate dielectric
Entirely Solution Processed Devices
July 6, 2015
July 6, 2015
July 6, 2015
23
23
23
23
HP Confidential
GSH, page 23
Device Characterization
•
Parallel-Plate Capacitor or MIM (Metal Insulator
Metal)
– Device Structure
• Insulator material between two metal plates
–
MIM Characterization
• Loss Tangent
• Permittivity
• Breakdown Strength
July 6, 2015
July 6, 2015
July 6, 2015
24
24
24
24
HP Confidential
GSH, page 24
Dielectric Performance
Material
ATO
SiO2
Hafsox/La
(Thermal)
Aluminum Oxide
Phosphate
Loss Tangent at 1kHz (%)
0.7-1.3
<0.01
0.30-0.70
0.9-1.4
Permittivity @ 1kHz
9-16
3.9
9-12
4
Breakdown Strength (MV/cm)
4-5
6-9
4-5
4-5
Leakage Current Density at 1 MV/cm (nA/cm^2)
0.3-1
Sample Size
– Hafsox
•
–
1-10
1-60
References
– ATO
•
36 substrates, 216 devices
Aluminum Oxide Phosphate
–
Jeff Bender
SiO2
• 2 substrate, 12 devices
July 6, 2015
July 6, 2015
July 6, 2015
1-10
•
HP Confidential
Handbook of Thin Film Technology
25
25
25
25
GSH, page 25
Device Characterization
•
Thin Film Transistor
– Device Structure
• Bottom-Gate
Physical vapor deposition
Solution based deposition
July 6, 2015
July 6, 2015
July 6, 2015
Substrate provided by HP
HP Confidential
26
26
26
26
GSH, page 26
Device Characterization
•
Thin Film Transistor Characterization
– ID-VDS
• DC
• Qualitative Characteristics
• Current Drive
–
ID-VGS
• DC
• Mobility (VDS = small, typically 1 V)
• Von
– Depletion vs. Enhancement Mode
• On-to-off Ratio (VDS = large, typically 30 V)
– Device Geometry
– Gate Leakage
July 6, 2015
July 6, 2015
July 6, 2015
27
27
27
27
HP Confidential
GSH, page 27
Solution Deposited Thin Films
Device Type
Motivation
PVD zinc tin
Show feasibility of Hafsox/La as
oxide-Hafsox/La gate insulator
Tin oxide
phosphate
Zinc oxide
Zinc oxideHafsox/La
Solution based channel
deposition
Solution based channel
deposition
Low temperature integration of
solution processed channel and
gate insulator
July 6, 2015
July 6, 2015
July 6, 2015
28
28
28
28
HP Confidential
GSH, page 28
Sputtered ZTO on
Hafsox-Hafsox/La
Annealed at 325 °C
VGS = 0 to 20 V
in 5 V Steps
Anomalous
Curve at 0
VGS
July 6, 2015
July 6, 2015
July 6, 2015
VGS = 0 to 10 V
in 1 V Steps
29
29
29
29
HP Confidential
GSH, page 29
Sputtered ZTO on Hafsox/La
Annealed at 325 °C
VGS = 0 to 10 V
in 1 V Steps
VON = 1 V On-to-Off ~106
July 6, 2015
July 6, 2015
July 6, 2015
30
30
30
30
HP Confidential
GSH, page 30
Solution Deposited Thin Films
Device Type
Motivation
PVD zinc tin
Show feasibility of Hafsox/La as
oxide-Hafsox/La gate insulator
Tin oxide
phosphate
Zinc oxide
Zinc oxideHafsox/La
Solution based channel
deposition
Solution based channel
deposition
Low temperature integration of
solution processed channel and
gate insulator
July 6, 2015
July 6, 2015
July 6, 2015
31
31
31
31
HP Confidential
GSH, page 31
Spin-Coated Tin Oxide Phosphate
Annealed at 500 °C
VGS = 0 to 40 V
in 5 V Steps
Max
Current
Drive of
225nA
July 6, 2015
July 6, 2015
July 6, 2015
VON = -7V
On-to-Off ~104
32
32
32
32
HP Confidential
GSH, page 32
Solution Deposited Thin Films
Device Type
Motivation
PVD zinc tin oxideHafsox/La
Show feasibility of Hafsox/La as gate
insulator
Tin oxide
phosphate
Zinc oxide
Zinc oxideHafsox/La
Solution based channel deposition
Solution based channel deposition
Low temperature integration of
solution processed channel and gate
insulator
July 6, 2015
July 6, 2015
July 6, 2015
33
33
33
33
HP Confidential
GSH, page 33
Spin-Coated Zinc Oxide on SiO2
Max
Current
Drive of
37μA
Annealed at 600 °C
VON = -16V
VGS = 0 to 40 V
in 5 V Steps
July 6, 2015
July 6, 2015
July 6, 2015
On-to-Off ~104
34
34
34
34
HP Confidential
GSH, page 34
Solution Deposited Thin Films
Device Type
Motivation
PVD zinc tin oxideHafsox/La
Show feasibility of Hafsox/La as gate
insulator
Tin oxide
phosphate
Zinc oxide
Zinc oxideHafsox/La
Solution based channel deposition
Solution based channel deposition
Low temperature integration of
solution processed channel and gate
insulator
July 6, 2015
July 6, 2015
July 6, 2015
35
35
35
35
HP Confidential
GSH, page 35
Spin-Coated
Zinc Oxide on Hafsox/La
Max Current
Drive of 1μA
Annealed at 325 °C
VGS = 0 to 40 V
in 5 V Steps
VON = -24V
July 6, 2015
July 6, 2015
July 6, 2015
On-to-Off ~104
36
36
36
36
HP Confidential
GSH, page 36
Summary of solution
deposited thin films
•
•
•
•
•
Modified Hafsox/La was demonstrated as a gate
dielectric
Aluminum oxide phosphate exhibited uniform MIM
breakdown characteristics
TOP (tin oxide phosphate) by solution deposition was
demonstrated as a channel layer
ZnO by solution deposition was demonstrated as a
channel layer
Solution deposited channel and dielectric layers were
integrated into transistor devices
July 6, 2015
July 6, 2015
July 6, 2015
37
37
37
37
HP Confidential
GSH, page 37
Inkjet Deposition
Yu-Jen Chang
Outline
Semiconductor Material – Zinc Indium Oxide (ZIO)
Previous work
Channel layer patterning
Device fabrication and characterization
Precursor solution study
Dielectric Material - Hafsox
Precursor solution
Device fabrication and characterization
Summary and ongoing work
July 6, 2015
July 6, 2015
July 6, 2015
39
39
39
39
HP Confidential
GSH, page 39
Zinc Indium Oxide (ZIO)
Previous work
Spin coating
 Indium and zinc chlorides were combined with gluconic
acid to form the aqueous precursor solution.
 The precursor was spin-coated and heated at 130ºC.
Additional heating was employed at temperatures in the
range 300-575ºC.
 The depletion –mode ZIO transistor had shown an
incremental mobility of ~ 0.05 cm2/V-sec at Vgs = 20 V.
Von ~ -20 V and an on-to-off ratio of approximately 103.
July 6, 2015
July 6, 2015
July 6, 2015
40
40
40
40
HP Confidential
GSH, page 40
Zinc Indium Oxide (ZIO)
Previous work
Inkjet printing
 ZIO thin films using diluted stock solution were prepared via
inkjet printing.
 Bottom gate ZIO MISFETs on oxidized silicon coupons were
fabricated with different post annealing temperature ranging
from 300 to 600oC.
 Light source was employed to stabilize the thin film and
overcome the de-wetting problem.
 No gate-modulated transistor behavior were obtained for Inkjet
printed ZIO TFT devices.
July 6, 2015
July 6, 2015
July 6, 2015
41
41
41
41
HP Confidential
GSH, page 41
Zinc Indium Oxide (ZIO)
Inkjet printing
Growth Mechanism
Metal halide
precursor solution
Inkjet printing
O2 source +H2O
Acetonitrile
Evaporation
Post annealing
Desorption
Liquid thin film
Metal oxide
Si coupon substrate
Si coupon substrate
July 6, 2015
July 6, 2015
July 6, 2015
HCl
42
42
42
42
HP Confidential
GSH, page 42
Zinc Indium Oxide (ZIO)
Inkjet printing
 An alternative ink solution was prepared by dissolving
0.015M of ZnCl2 and 0.015M of InCl3 in 25ml acetonitrile
at room temperature.
 First pass bottom gate ZIO MISFET was fabricated.
Gate-modulated transistor behavior was obtained but
large gate leakage currents were found.
 To avoid this problem is to pattern the semiconductor
channel layer
July 6, 2015
July 6, 2015
July 6, 2015
43
43
43
43
HP Confidential
GSH, page 43
Zinc Indium Oxide (ZIO)
Channel layer patterning
~12 mm
Inkjet Printing
3
Device
S/D contacts
10
Characterization
15 mm

Stripe patterned ZIO thin films were thermal ink-jetted on
Si/SiO2 test coupon to fabricate ZIO TFTs.
 Gate leakage current was significantly reduced by 2 to 3
orders of magnitude for stripe patterned (~3mm x12mm)
ZIO TFTs (1e-10~1e-13 Amp at Vg=0V) comparing to
non-stripe patterned ones.
July 6, 2015
July 6, 2015
July 6, 2015
44
44
44
44
HP Confidential
GSH, page 44
Zinc Indium Oxide (ZIO)
Device fabrication and characterization

ZnCl2 and InCl3 were dissolved in 25 ml of acetonitrile
with a molar ratio of 1 to 1 (0.015M) as precursor solution
for ink jet printing.

The modified HP 1220C inkjet printer was used to print
the thin ZIO layer.

Working ZIO TFTs were obtained from films annealed at
325oC, 400oC, 600oC, and 800oC (in acetonitrile); 375oC
(in ethanol)
July 6, 2015
July 6, 2015
July 6, 2015
45
45
45
45
HP Confidential
GSH, page 45
Zinc Indium Oxide ID-VDS Characteristic
(600 ºC, Acetonitrile)
2.0E-05
2.5E-06
W/L = 7
L = 200 um
ID (A)
1.5E-06
1.0E-05
1.0E-06
5.0E-06
IG(A)
2.0E-06
1.5E-05
5.0E-07
0.0E+00
0.0E+00
0
10
20
30
VDS (V)
• I-V characteristics for inkjet ZIO TFTs annealed at 600 ºC for 1 hour
using acetonitrile as the precursor solvent.
W/L=7 and µinc ~0.7 cm2/V-s.
July 6,•2015
July 6, 2015
July 6, 2015
HP Confidential
46
46
46
46
GSH, page 46
Zinc Indium Oxide ID-VDS Characteristic
(800 ºC, Acetonitrile)
1.E-09
6.E-07
W/L = 7
L = 200 um
1.E-09
4.E-07
8.E-10
3.E-07
6.E-10
2.E-07
4.E-10
1.E-07
2.E-10
0.E+00
0.E+00
0
20
10
IG(A)
ID (A)
5.E-07
30
VDS (V)
• I-V characteristics for inkjet ZIO TFTs annealed at 800 ºC for 1 hour
using acetonitrile as the precursor solvent.
W/L=7 and µinc ~0.013 cm2/V-s.
July 6,•2015
July 6, 2015
July 6, 2015
HP Confidential
47
47
47
47
GSH, page 47
Zinc Indium Oxide ID-VDS Characteristic
(375 ºC, Ethanol)
8.E-09
7.E-09
W/L = 7
L = 200 um
6.E-08
6.E-09
5.E-09
4.E-09
3.E-09
ID (A)
5.E-08
4.E-08
3.E-08
2.E-08
IG(A)
7.E-08
2.E-09
1.E-09
0.E+00
1.E-08
0.E+00
0
10
20
30
VDS (V)
• I-V characteristics for inkjet ZIO TFTs annealed at 375 ºC for 1 hour
using ethanol as the precursor solvent.
W/L=7 and µinc ~0.005 cm2/V-s.
July 6,•2015
July 6, 2015
July 6, 2015
HP Confidential
48
48
48
48
GSH, page 48
Zinc Indium Oxide (ZIO)
SEM analysis on a working TFT using inkjet ZIO thin film
The top view image of the
gate region
The cross-sectional view
of the gate region,
the thickness of ZIO thin
film is ~10 to 15nm.
July 6, 2015
July 6, 2015
July 6, 2015
The top view image of the
region outside the device
gate
49
49
49
49
HP Confidential
GSH, page 49
Zinc Indium Oxide (ZIO)
(a) AMD cleaning
Precursor solution study
Precursor solutions listed in Table were inkjet printed on Si/SiO2 test coupon
for film formation and patterning study.
Solvents
Film Quality
Patterning
(b) AMD cleaning
Water/Acetonitrile
(10 to 90% of water)
Water/Ethanol
(10 to 90 % of water)
Acetonitrile
Poor
Dewetting
Isolated dots
Fair
Dots on the surface
Fine
Tiny Dots on the surface

Ethanol
July 6, 2015
July 6, 2015
July 6, 2015
HP Confidential
No pattern

Fine
Solution spread out
No pattern
50
50
50
50
GSH, page 50
Zinc Indium Oxide (ZIO)
Precursor solution study
Volumetric ratios for Ethanol/Acetonitrile
5/95%
14.66o
10/90%
25/75%
10.27o
<10o
Increasing contact angle
July 6, 2015
July 6, 2015
July 6, 2015
50/50%
75/25%
<10o
<10o
Not much different by changing
Ethanol/Acetonitrile volumetric ratio
HP Confidential
51
51
51
51
GSH, page 51
Zinc Indium Oxide (ZIO)
Summary
Processing Method
Spin coating
Inkjet printing
Patterning
Non-available
Available
Device Type
Depletion-Mode
Enhancement-Mode
Device Performance
µinc ~0.05 cm2 V-1 s-1
µinc ~0.7 cm2 V-1 s-1
Ongoing work
Solvent
Thickness
Morphology
Zn/In
ratio
July 6, 2015
52
52
52
52
July 6, 2015
July 6, 2015
HP Confidential
GSH, page 52
Hafnium Oxide Sulfate (Hafsox)
Precursor solution ,Device fabrication and
characterization
HfOCl2 ,,La2(SO4)3 ,H2SO4 and DI water was used for
preparing the Hafsox precursor solution for spin coating
process.
 Diluted precursor solution suitable for inkjet printing process
was prepared by 0.01M HfOCl2 and 0.002M H2SO4 in
solution of water/ethanol (ethanol is 10% of the solution
volume).
 Single layer and multilayer deposition were performed
through inkjet printing process for depositing Hafsox thin film.
 Hafsox thin film deposition via inkjet printing on Tantalum
surface was performed and device was tested by MIM
capacitor structure.

July 6, 2015
July 6, 2015
July 6, 2015
53
53
53
53
HP Confidential
GSH, page 53
Hafnium Oxide Sulfate (Hafsox)
Scanning Electron Microscopy (SEM) characterization
Defects and pinholes were observed in SEM micrograph
July 6, 2015
July 6, 2015
July 6, 2015
54
54
54
54
HP Confidential
GSH, page 54
Hafnium Oxide Sulfate (Hafsox)
Pen autopsy images of a used inkjet cartridge after
printing Hafsox precursor solution
Completely closed nozzle
with precipitate
July 6, 2015
July 6, 2015
July 6, 2015
Resistor
surface with
precipitate
Partially closed nozzle
with precipitate
HP Confidential
55
55
55
55
GSH, page 55
Hafnium Oxide Sulfate (Hafsox)
Summary

Inkjet printed Hafsox dielectric layer could not pass the
MIM test for our study.

SEM measurements indicated pin holes and defects on
inkjet printed Hafsox thin films.

Hafsox precursor solution had damaged and blocked the
inkjet cartridge nozzles via precipitate around the nozzle
opening and the resistors.

This Hafsox precursor solution is not compatible with
current inkjet printing system.
July 6, 2015
July 6, 2015
July 6, 2015
56
56
56
56
HP Confidential
GSH, page 56
4/5/2005
Material Exploration
Hai Chiang
Jason Stowers
Amorphous Oxide Semiconductors
•
n-type amorphous oxide semiconductors
–
Composed of heavy-metal cation(s) with
(n-1)d10ns0 (n≥4) electronic configuration
• conduction band primarily derived of
spherical s orbitals
• cation examples include In, Zn, Sn, Ga, Cd, etc.
• material example: indium oxide doped with tin (ITO)1
–
Methods employed in exploration:
• rf sputtering from ceramic targets
• shadow mask pattering
• bottom-gate structures fabricated on oxide Si coupons.
1. Y. Shigesato and D. C. Paine, Appl. Phys. Lett. 62, 1268 (1993)
July 6, 2015
July 6, 2015
July 6, 2015
58
58
58
58
HP Confidential
GSH, page 58
Previously explored materials:
Zinc tin (indium) oxide
Temp
(C)
Zinc tin oxide
(1:1 mol)1,2
Zinc indium oxide
(2:1 mol)2,3
inc
(cm2/V-s)
Von
(V)
inc
(cm2/V-s)
Von
(V)
RT
-
-
0.4
10
200
<0.01
25
2
-2
400
16
0
40
-35
600
26
-1
28
-50
1. R. Hoffman, HP internal document, WKRP, Oct. 22, 2003
2. H. Chiang, J. Wager, R. Hoffman, et al., Appl. Phys. Lett. 86, 013503 (2005)
3. H. Chiang and R. Hoffman, HP internal document, WKRP, Aug. 19, 2004
4. N.Dehuff, E. Kettenring, D. Hong, et al., J. Appl. Phys. 97, 064505 (2005)
July 6, 2015
July 6, 2015
July 6, 2015
HP Confidential
59
59
59
59
GSH, page 59
8.E-04
log (ID(A))
Increasing VGS
ID (A)
6.E-04
4.E-04
2.E-04
0.E+00
0
10
20
30
0
-2
-4
-6
-8
-10
-12
0
-2
-4
-6
-8
-10
-12
W/L = 5
L = 200 µm
VDS = 30 V
-10
0
10
20
30
log (|IG|(A))
Indium gallium oxide (1:1 mol):
DC Electrical Characteristics
40
VGS (V)
VDS (V)
VGS = 0 to 30 V
in 10 V steps
• Channel layer subjected to 600 ºC anneal.
• ITO source/drain contacts.
July 6, 2015
July 6, 2015
July 6, 2015
60
60
60
60
HP Confidential
GSH, page 60
Indium gallium oxide (1:1 mol):
Channel mobility characteristic
W/L = 5
VDS = 1 V
15
µinc ~ 16 cm2/Vsec
2
inc (cm /V s)
20
10
5
0
-10
0
10
20
30
40
VGS (V)
•
Fairly ideal, increases then saturates.
July 6, 2015
July 6, 2015
July 6, 2015
61
61
61
61
HP Confidential
GSH, page 61
Indium gallium oxide (1:1 mol):
Performance
Temp
(C)
Zinc tin oxide (1:
1 mol)
Zinc indium
oxide (2:1 mol)
Indium gallium
oxide (1:1 mol)
inc
(cm2/V-s)
Von
(V)
inc
(cm2/V-s)
Von
(V)
inc
(cm2/V-s)
Von
(V)
RT
-
-
0.4
10
-
-
200
<0.01
25
2
-2
-
-
400
16
0
40
-35
7
7
600
26
-1
28
-50
15
1
July 6, 2015
July 6, 2015
July 6, 2015
62
62
62
62
HP Confidential
GSH, page 62
Conclusions and path forward
Conclusions:
• Indium gallium oxide with qualitatively ideal ID-VDS
characteristics.
• Channel mobility characteristics comparable to zinc tin
oxide, but lower magnitude.
• Additional process flexibility - indium gallium oxide
etches in HCl.
Path Forward:
• Explore stoichiometric variations of indium gallium oxide
– literature suggests that performance increases with
indium concentration.1
• Optimize deposition parameters.
1.
T. Minami, Y. Takeda, et al., JVST A, 15, 958 (1997).
July 6, 2015
July 6, 2015
July 6, 2015
HP Confidential
63
63
63
63
GSH, page 63
P-Type Material Investigation
•
•
•
•
Recent work in this group has found several n-type
materials with an amorphous crystal structure. 1,2
We hope to use additional properties of amorphous
structure as a route to forcing candidate materials toward
p-type behavior.
The materials will be deposited amorphously by using low
substrate temps during e-beam deposition.
Crystallization will be frustrated through addition of ~10 to
40% Zn, In, Sn or combination there of.
1.
Dehuff, N. L.; Kettenring, E. S.; Hong, D.; Chiang, H. Q.; Wager, J. F.; Hoffman, R. L.; Park, C.-H.; Keszler, D. A..
Transparent thin-film transistors with zinc indium oxide channel layer. Journal of Applied Physics (2005), 97(6)
2.
Chiang, H. Q.; Wager, J. F.; Hoffman, R. L.; Jeong, J.; Keszler, D. A.. High mobility transparent thin-film transistors with
amorphous zinc tin oxide channel layer. Applied Physics Letters (2005), 86(1)
July 6, 2015
July 6, 2015
July 6, 2015
64
64
64
64
HP Confidential
GSH, page 64
Candidate materials;
Bi2O3 and Sb2O3
•
•
Known Materials
– ZnO, Zn2+; [Ar] 3d10 4s0
– Cu2O, Cu1+; [Ar] 3d10 4s0
n-type
p-type
Candidate materials
– Bi2O3, Bi3+; [Xe] 5d10 6s2
– Sb2O3, Sb3+; [Kr] 4d10 5s2
p-type?
p-type?
July 6, 2015
July 6, 2015
July 6, 2015
65
65
65
65
HP Confidential
GSH, page 65
Energy Band Levels in Bi2O3 and Sb2O3
July 6, 2015
July 6, 2015
July 6, 2015
66
66
66
66
HP Confidential
GSH, page 66
Local metal atom coordination
Distorted Octahedral Environment for Bi in Bi2O3,
bond length ~2.1-~3 Ang
Proposed regular Octahedral Environment for Bi in
amorphous Bi2O3 , bond length 2.4 Ang
July 6, 2015
July 6, 2015
July 6, 2015
67
67
67
67
HP Confidential
GSH, page 67
Bi2O3 Band Structure
6P
2P
6S
July 6, 2015
July 6, 2015
July 6, 2015
68
68
68
68
HP Confidential
GSH, page 68
Progress To Date
•
•
•
Depositions are completed for
compositional arrays with Bi2O3 and Sb2O3
Optical and electrical measurements are
underway
Crystallization temperature being
determined
July 6, 2015
July 6, 2015
July 6, 2015
69
69
69
69
HP Confidential
GSH, page 69
Summary of Solution Deposited Film
Strategies
• Semiconductor films will be made more
dense to achieve higher mobility.
• Dielectric permittivity will be increased
through a layering technique.
• Buffer films will be employed to improve
film interfaces.
July 6, 2015
70
Inorganic Devices via Additive Processing
Future Work:
• Continue efforts on development of oxide electronics
• expand learnings on device performance of
solution processed vs. physical processed devices
• demonstrate high mobility p-type behavior
• demonstrate dielectric permittivity ~ 50
• demonstrate transistor channel mobilites ~ 50
• Extend program to include nonoxide channel materials
• initial efforts on crystalline and amorphous
tellurides
• demonstrate transistor channel mobilities ~ 100 71
July 6, 2015
Backup Slides
July 6, 2015
July 6, 2015
July 6, 2015
72
72
72
72
HP Confidential
GSH, page 72
Zinc Indium Oxide (ZIO)
1.80E-06
1.60E-06
Vg = -20
Vg = -16
1.40E-06
Vg = -12
1.20E-06
Ids (A)
Vg = -8
1.00E-06
Vg = -4
8.00E-07
Vg = 0
Vg = 4
6.00E-07
Vg = 8
4.00E-07
Vg = 12
2.00E-07
Vg = 16
Vg = 20
0.00E+00
-2.00E-07
0
5
10
15
20
25
30
35
40
Vds (V)
Drain current – drain voltage characteristics for a spincoated ZIO transistor with a W/L ratio of 7 and 100 nm of
thermal SiO2 as the gate dielectric.
July 6, 2015
July 6, 2015
July 6, 2015
HP Confidential
73
73
73
73
GSH, page 73
Zinc Indium Oxide (ZIO)
Precursor solution study
Contact angle measurement
100%-acetonitrile
100%-Ethanol
Θ
Contact angle – 51o
Contact angle - ~ 0o
July 6, 2015
July 6, 2015
July 6, 2015
74
74
74
74
HP Confidential
GSH, page 74
Hafnium Oxide Sulfate (Hafsox)
Solubility of aqueous solution of HfOCl2 and H2SO4
0.1
total Sulfate (M)
0.08
0.06
0.04
0.02
0
0
July 6, 2015
July 6, 2015
July 6, 2015
0.02
0.04
total Hafnium (M)
HP Confidential
0.06
0.08
75
75
75
75
GSH, page 75
Hafnium Oxide Sulfate (Hafsox)
Atomic force microscopy (AFM) characterization
The 2-D AFM micrograph and roughness
analysis for a single coat Hafsox thin film
with July
ave.6,roughness
~0.688nm.
2015
The 3-D AFM micrograph for a single coat
Hafsox thin film with thickness around 35nm.
July 6, 2015
July 6, 2015
HP Confidential
76
76
76
76
GSH, page 76
Backup Slides: ZTO 700 ºC XRD
Zn2SnO4 (311)
1000
Counts
Zn2SnO4 (511)
Zn2SnO4 (531)
500
Zn2SnO4 (220)
Zn2SnO4 (222)
Zn2SnO4 (533)
0
20
30
40
50
60
70
Position - 2 (°)
July 6, 2015
July 6, 2015
July 6, 2015
77
77
77
77
HP Confidential
GSH, page 77
Reference: Periodic Table
July 6, 2015
July 6, 2015
July 6, 2015
78
78
78
78
HP Confidential
GSH, page 78