Applications of Sputtering to Silicon Solar Cells Ar 15 sccm
Transcript of Applications of Sputtering to Silicon Solar Cells Ar 15 sccm
ANU College of
Engineering & Computer Science
Applications of Sputtering to Silicon Solar Cells By Xinyu Zhang, ANU Research School of Engineering, [email protected] Supervisors: Professor Andres Cuevas, Dr. Andrew Thomson
1 Introduction
Photovoltaic solar energy is believed to be an attractive alternative for
future’s energy consumption. Since the first silicon solar cell was
developed in 1954 [1], solar energy has been continuously competing with
other energy resources. As a result, the “cost of solar power” is always the
main theme in the history of solar cells, and it will guide future research
directions as well.
2 Motivation
There are two ways of reducing solar power cost by
improving solar cells:
Improve solar cell Reduce manufacturing costs
Time Solar Power
Cost
Applications Achievement
1950s
~
1970s
~ 300 $/W Only cost-effective in space
applications.
1970s
~
1980s
100 $/W
→ 10 $/W
Thanks to the developments of
screen-printing technique and
solar panels, cost was greatly
reduced. Applications in remote
areas become competitive with
power.
1990s ~
Today 10 $/W
→ 2 $/W
Incredible development for solar
industry [2]:
• Growth rate over 44% per year.
• Global cumulative installed
capacity over 70 GW in 2011.
In the
future
“solar energy could provide a
third of the global final energy
demand after 2060”
-- International Energy Agency
2011 [3]
Lab made solar cells:
• High efficiency
• Expensive to make
Industrial solar cells:
• Relative low efficiency
• Cheap to make
Cost-effective techniques for higher efficiency solar cells are
required, and sputtering creates the potential to achieve this.
3. Background
Advantages of sputtering:
• Large-scale processing
systems available
• Non-toxic; non-explosive
and easy-produced target
source
• Low temperature process
• Relatively cheap
RF Power
4. Research objects and initial results
The main applications of sputtering in my project are:
• Surface passivation layer deposition
• Back surface field formation
• Rear contact formation
Last year’s research shown:
Sputtering conditions for AlOx surface passivation
layer deposition can be well controlled [4]
1.0 1.5 2.0 2.5 3.00
1
2
3
4
5
6
7
8
9
10
O2 flow rate (sccm)
Dep
ositio
n R
ate
(n
m/m
in)
Ar 35 sccm
Ar 30 sccm
Ar 25 sccm
Ar 20 sccm
Ar 15 sccm
Power = 300 W
Pressure = 3 mTorr
100 150 200 250 300
0
1
2
3
4
5
6
7
8
9 1 mTorr
3 mTorr
5 mTorr
Power (W)
De
po
sitio
n R
ate
(n
m/m
in)
Ar = 30 sccm
O2 = 1.6 sccm
Effective surface passivation for crystalline silicon can
be achieved [4]
5. Conclusions: Surface passivation for crystalline silicon by sputtered AlOx
films have been studied, and that is the most important
application in this project. It has been proved that effective
surface passivation can be achieved by this method. Future
work will be conducted on further study of sputtering
technique and developing other applications to solar cells.
[1] D. M. Chapin, et al. J. Appl. Phys., 25 (5), 676-677.
[2] International Renewable Energy Agency, “Solar Photovoltacs”, Vol 1 (4/5), 2012.
[3] International Energy Agency, “Solar Energy Perspectives”, 2011.
[4] X. Zhang, et al. 38th IEEE PVSC, Austin, TX, 2012.