Download Modified Oxide Tool

Modified Oxide Tool
System Capabilities
• Vertical Injection chamber
• Water cooled Head
• Upto 4 MO sources
• Process Gas: O2
• Carrier Gas: N2
• Dopant Gas: NH3, N2O, SiH4,
PH3
• Liquid injection capability with
upto 2 Liquid Injection Sources
• New Control System with all the
features
Control Software Capabilities
• Complete monitoring of all
system parameters
• Advanced Recipe making and
manipulation options
• Pulsed growth control and steps
looping options
Ian Ferguson
([email protected])
ZnO Overview
September 2009 Slide [1]
Electrical and Computer Engineering
Effect of ZnO MOCVD growth conditions on point defect formation
Large variation in reported growth conditions
•
•
•
•
Low oxygen chemical
potential limit
Substrate material - bare Sapphire, GaN-templates,
ScAlMgO4, ZnO, LiNbO3
Growth Temperature - 200 - 780°C, ~550-600°C
Precursor – Oxygen: O2, alcohols (t-BuOH, i-PrOH), CO2, N2O,
NO2, NO, H2O, H2O2, tetrahydro furan
– Zinc:
DMZn, DEZn, Alkylzinc alkoxides (MeZn(OPri),
MeZn(OBut)), Zn acetate
Carrier gas - N2, Ar, O2, He, H2, Air, H2O
7x1017
600
30
Resistivity (Ω cm)
20
300
200
10
100
Data from
Table 1 in Y. Ma et
al., J. Cryst.
Growth 255 (2003)
303-307
0
0
20
30
40
50
60
Mobility (cm2/ V s)
400
5x1017
4x1017
3x1017
2x1017
1x1017
0
Carrier Concentration (cm-3)
6x1017
500
70
Oxygen Partial Pressure (Pa)
High oxygen chemical
potential limit
J.-L. Zhao et al., J. Phys.: Condens. Matter 18, (2006)
1495-1508
Understanding of point defect formation essential to achieving stable p-type ZnO
Ian Ferguson
([email protected])
ZnO Overview
September 2009 Slide [2]
Electrical and Computer Engineering
Electrical and optical properties
Wavelength (nm)
410
0.5
Below Hall 0.0
detection limit
of ~3x1016cm-3
50 Torr
2E17 750rpm
45
40
35
1.5E17
30
25
1E17
20
15
•
•
T = 293 K
10
200 300 400 500 600 700 800 900 1000
675
450
VI/II Ratio
Undoped films are nominally n-type with
low electron mobilities
Higher VI/II  few VO  fewer deep
•
defect centers
Carrier concentration v. rms surface
•
roughness suggests surface states as source
of carriers
Ian Ferguson
([email protected])
370
Tgrowth=500C
50 Torr
750rpm
VI/II ratio
900
220
•
380
Eexc.= 3.81 eV
PL Intensity (norm. units)
1.0
50
2.5E17 Tgrowth=500C
390
ZnO/Sapphire
RMS Surface Roughness (nm)
1.5
Carrier Concentration (cm-3)
Mobility (cm2/V-s)
2.0
400
Eexc.= 5.0 eV
3.1
LO
LO
3.2
3.3
Energy (eV)
3.4
Increase in VI/II ratio: red-shift of near
band-edge emission of PL spectrum
LO phonon replica (increase in Huang
Rhys factor) and/or additional defect bands
with increasing VI/II ratio
ZnO Overview
September 2009 Slide [3]
Electrical and Computer Engineering
Raman
ZnO modes at 330cm-1,
375cm-1, and 437cm1
ZnO:N modes at 275cm1, 510cm-1, 570cm-1,
640cm-1
Ian Ferguson
([email protected])
ZnO Overview
September 2009 Slide [4]
Electrical and Computer Engineering
Pioneer Research In Nuclear Detection
GaTech
P
GT
@
R
I
N
Each area requires specific
applications & technologies
Focused Research
Program
Pioneer Research
in Nuclear Detection
Each threat & pathway
yields different signatures
D
High Yield Explosives Detection
Threat & Pathway-based
Analysis
Loose Nuke
Signatures
Detection
Dirty Bomb
Signatures
Detection
PRIND Specialized Research, Development & Prototyping
Leading to
Game Changing Technology
Ian Ferguson
([email protected])
ZnO Overview
September 2009 Slide [5]
Electrical and Computer Engineering
Multiferroics Overview
Magnetism, Ferroelectricity,
and Electromagnetic waves
interplay can revolutionize
optoelectronic devices.
E
V
hν
+
H
ε
µ
H
-
Multiferroic Materials
Growth and Integration
Integrated ferroelectric/ferromagnetic
devices in only complex oxides
New Prozperties of
Existing Materials
Waveguide
BiMnO3
Single Phase
Vs Multiphase
BaTiO3
E
H
BiMnO3
p-GaN
E
H
p-ZnO:N
Active Region
Active Region
n-GaN
n-ZnO
Sapphire
Sapphire
CoFe2O4
BaTiO3
Ian Ferguson
([email protected])
Integrated ferroelectric
in complex oxides and ferromagnetic
devices in semiconductors
ZnO Overview
September 2009 Slide [6]
Complex oxide/ZnO
Complex oxide/GaN
New device technology in existing
devices and manufacturing
infrastructure
Electrical and Computer Engineering