Solar Cells Fabrication Technologiesee143/fa10/lectures/Lec_26.pdf · Professor N Cheung, U.C....

Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

Solar Cells Fabrication

Technologies

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•Crystalline Si Cell Technologies

•Amorphous Si Cell Technologies

•Thin Film Cell Technologies

For a comprehensive tutorial on solar cells in general,

see www.udel.edu/igert/pvcdrom

Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

Global Energy Sources projection

Source: World Energy Council

Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

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The Growth Rate Captures the Attention

Source: AMAT

Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

Solar Facts

•The earth receives more energy from the sun in just

one hour than the world uses in a whole year.

•1% of the land today used for crops and pasture could

supply the world's total energy consumption.

•The Sun provides 1020 Watts/meter² peak power at sea-

level

Cell efficiency of 10% translates to ~100W/meter2

Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

Commonly Known Solar Cell Materials

Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

Fraunhofer

Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

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Beside efficiency, there are other considerations for ultilization

Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

Projected Module Cost

Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

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Energy Content

EG silicon ~ 200 kWh/kg

Solar Grade Si ~ 50kWh/kg

MG silicon ~ 20kWh/kg

Richard Corkish ,Solar Progress, (1997)

Energy Payback time

Monocrystalline Si cell ~ 4 years

Polycrystalline Si cell 1.6 to 2.7 years

Amorphous Si cell 0.9 to 1.6 years.

Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

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Crystalline

Silicon

Amorphous

SiliconCIGS CdTe Organic

Conversion

Efficiency13-18% 5-10% 10-12% 10.5% 5%

Current cost

per Watt* $2.5-3.5 $2-2.5$0.6

(predict)

$1.3

<$1

(predict)

Material

ShortageNo Silane Indium Te(?) No

Toxic

SubstanceNA NA

Cadmium

Selenium

Cadmium

TelluriumNA

Reliability Excellent Fair Good Good Poor

Company in

the field

Suntech,

SunPower

AMAT,

Dupont

Nanosolar,

SolyndraFirst Solar Konarka

Comparison of commercial PV

Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

•Crystalline solar cells are usually wafers, about 0.3 mm thick, sawn from Si

ingot

• 15% efficiency cells deliver

15 to 60 W/m² or 0.45-1.35

kWh/m²/day (annual day and

night average) in North

America

Si Crystalline Solar cells are just large area semiconductor diodes

Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

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From Ingot to Module

Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

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From Ingot to Module (cont.)

Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

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From Sand to Silicon

Process generates four tons of silicon tetrachloride

liquid waste for each ton of polysilicon produced.

Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

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Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

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Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

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Minimize Kerf Loss

Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

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Generic Crystalline Si Cell Processing

Al-Ag paste

* Al-Ag fuses through SiNx to form ohmic contact

Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

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Backside Al contact

(BSF= back surface field p+ layer)

Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

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Max T =950C

Belt Furnace

Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

50 MW fab cell line.

(Source: Applied Materials)

Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

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Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

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Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

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Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

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Antireflection Coating Materials

Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

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Diagnosis of Crystalline-Silicon Solar- Cells Utilizing Electroluminescence: save

production costs by sorting out defective solar-cells in an early stage

Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

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Module

Packaging

Source: Spire Corp

Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

Crystalline Si on Glass (CSG) Solar Cell

* All fabrication done with Laser processing and low-temperature PECVD

Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

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Sliver Cell

A wafer (assume 150mm diameter) configured as a conventional solar cell has an area

of 177cm2. However, the same wafer, when processed to produce Sliver® cells, can be

used to cover up to 5,000 cm2 of module area, which is 30 times better than for

conventional technology.

Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

Both silicon and thin-film PV solutions require a reduction in cost/watt. (Source: Applied

Materials)

Motivation for amorphous Si Cell

Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

Rigid and Flexible a-Si Solar Cells

Cell efficiency, h = Voc × Jsc × FF

Pin

i- a-Si:H

Textured

TCOZnO

p- a-

SiC:H

n- a-Si:H

30% T Ag

Glass / TCO / p / i / n / Ag SS / ZnO / p / i / n /Ag

Opaque

(SS/Kapton)

Glass

Voc Doped layers

Jsc i-layer defect

density

Light trapping

FF i-layer defect density

Interfaces

Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

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Amorphous Si Deposition

Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

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Amorphous Si Deposition

Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

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Source: ULVAC Solar

a-Si Cell Manufacturing

Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

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Source: AMAT

Conceptual a-Si Cell Fab

Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

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CIGS Solar Cells

Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

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Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

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Source: pmc.org.tw

CIGS Manufacturing

Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

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Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

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Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

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Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

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Source: Ascent Solar

Roll-to-Roll Manufacturing

Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

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Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

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Needs MBE , MOCVD, or Layer Transfer

Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

Technology Evolution

c-Si

thin film

"New Concepts"

0

500

1000

1500

2000

2500

3000

3500

0

20

40

60

80

100

120

140

2002 2005 2010 2015 2020 2025 2030

MW GW30%p.a. 25%p.a.

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RENEWABLE ENERGY FOR EUROPE - RESEARCH IN ACTION

Professor N Cheung, U.C. Berkeley

Lecture 26EE143 F2010

Q: What are the major differences between

PV fabrication and IC/MEMS fabrication ?

•Patterning (alignment, size control)

•Doping

•Contact Formation

•Metallization

•Planarization

Q: What other process modules are not

commonly used in IC/MEMS fabrication ?