Solar Cells Fabrication Technologies by juanagao

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									EE143 F2010                                                             Lecture 26




                            Solar Cells Fabrication
                                Technologies


                                    •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                                                1
EE143 F2010                                                              Lecture 26



                              Global Energy Sources projection




                                                Source: World Energy Council
Professor N Cheung, U.C. Berkeley
EE143 F2010                                                          Lecture 26



                            The Growth Rate Captures the Attention




Professor N Cheung, U.C. Berkeley               Source: AMAT                  3
EE143 F2010                                                           Lecture 26




                                    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
EE143 F2010                                                    Lecture 26


                         Commonly Known Solar Cell Materials




Professor N Cheung, U.C. Berkeley
EE143 F2010                                      Lecture 26




                                    Fraunhofer




Professor N Cheung, U.C. Berkeley
EE143 F2010                                                         Lecture 26



     Beside efficiency, there are other considerations for ultilization




Professor N Cheung, U.C. Berkeley                                            7
EE143 F2010                                                 Lecture 26




                                    Projected Module Cost




Professor N Cheung, U.C. Berkeley
EE143 F2010                                                                       Lecture 26




                                       Energy Content

                               EG silicon           ~ 200 kWh/kg
                               Solar Grade Si       ~ 50kWh/kg
                               MG silicon           ~ 20kWh/kg


                                       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.

                                     Richard Corkish ,Solar Progress, (1997)
                                                                          9
Professor N Cheung, U.C. Berkeley
EE143 F2010                                                                             Lecture 26



                   Comparison of commercial PV
                             Crystalline Amorphous
                                                       CIGS        CdTe       Organic
                              Silicon      Silicon
      Conversion
                                13-18%    5-10%       10-12%       10.5%        5%
       Efficiency
                                                                    $1.3
     Current cost                                       $0.6
                               $2.5-3.5   $2-2.5                    <$1
      per Watt*                                       (predict)
                                                                  (predict)
        Material
                                    No    Silane      Indium        Te(?)       No
        Shortage
         Toxic                                       Cadmium      Cadmium
                                    NA     NA                                   NA
       Substance                                     Selenium     Tellurium

       Reliability            Excellent    Fair        Good        Good        Poor

      Company in Suntech,                 AMAT,      Nanosolar,
                                                                First Solar   Konarka
       the field SunPower                 Dupont      Solyndra

                                                                              10
Professor N Cheung, U.C. Berkeley
EE143 F2010                                                    Lecture 26


                        Si Crystalline Solar cells
               are just large area semiconductor diodes


                                    •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



Professor N Cheung, U.C. Berkeley
EE143 F2010                                                Lecture 26




                                    From Ingot to Module




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EE143 F2010                                               Lecture 26




                           From Ingot to Module (cont.)




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                           From Sand to Silicon




            Process generates four tons of silicon tetrachloride
             liquid waste for each ton of polysilicon produced.
                                                          14
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EE143 F2010                         Lecture 26




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EE143 F2010                                              Lecture 26




                                    Minimize Kerf Loss




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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                                                             18
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                               Backside Al contact




                                    (BSF= back surface field p+ layer)
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                                    Belt Furnace




                                      Max T =950C

Professor N Cheung, U.C. Berkeley                           20
EE143 F2010                                           Lecture 26

                           50 MW fab cell line.
                        (Source: Applied Materials)




Professor N Cheung, U.C. Berkeley
EE143 F2010                         Lecture 26




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EE143 F2010                                                       Lecture 26




                               Antireflection Coating Materials




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EE143 F2010                                                                                        Lecture 26




               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                                                                          26
EE143 F2010                         Lecture 26




          Module
         Packaging




    Source: Spire Corp
Professor N Cheung, U.C. Berkeley           27
EE143 F2010                                                              Lecture 26




                            Crystalline Si on Glass (CSG) Solar Cell




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

Professor N Cheung, U.C. Berkeley
EE143 F2010                                                                               Lecture 26


                                        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                                                                 29
EE143 F2010                                                                Lecture 26


                              Motivation for amorphous Si Cell




                       Both silicon and thin-film PV solutions require a
                          reduction in cost/watt. (Source: Applied
                                          Materials)
Professor N Cheung, U.C. Berkeley
EE143 F2010                                                                         Lecture 26




      Rigid and Flexible a-Si Solar Cells
                                               30% T Ag
                                                n- a-Si:H
                                                i- a-Si:H

                 Glass                            p- a-
                                                                         Opaque
                                    Textured      SiC:H ZnO            (SS/Kapton)
                                     TCO
            Glass / TCO / p / i / n / Ag                         SS / ZnO / p / i / n /Ag
            Voc  Doped layers
           Jsc  i-layer defect                                       Voc × Jsc × FF
                density                        Cell efficiency, h =
                       Light trapping                                      Pin

   FF  i-layer defect density
Professor N Cheung, U.C. Berkeley
EE143 F2010                                                   Lecture 26



                                    Amorphous Si Deposition




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EE143 F2010                                                   Lecture 26



                                    Amorphous Si Deposition




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EE143 F2010                                                      Lecture 26



                              a-Si Cell Manufacturing




                                           Source: ULVAC Solar
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                                    Conceptual a-Si Cell Fab




                                                        Source: AMAT
Professor N Cheung, U.C. Berkeley                                              35
EE143 F2010                         Lecture 26




Professor N Cheung, U.C. Berkeley
EE143 F2010                                            Lecture 26


                                    CIGS Solar Cells




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EE143 F2010                                                            Lecture 26



                                    CIGS Manufacturing




                                                  Source: pmc.org.tw
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EE143 F2010                         Lecture 26




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EE143 F2010                                                  Lecture 26




                          Roll-to-Roll Manufacturing




                                      Source: Ascent Solar
Professor N Cheung, U.C. Berkeley                                    43
EE143 F2010                         Lecture 26




Professor N Cheung, U.C. Berkeley           44
EE143 F2010                                                                Lecture 26




                                    Needs MBE , MOCVD, or Layer Transfer
Professor N Cheung, U.C. Berkeley                                                  45
EE143 F2010                                                                                               Lecture 26


                                                                                          c-Si
                                           Technology Evolution                           thin film
                                                                                          "New Concepts"

     MW                                                                            GW
                        30%p.a.                            25%p.a.
    3500                                                                            140
    3000                                                                             120
    2500                                                                             100
    2000                                                                             80
    1500                                                                             60
    1000                                                                             40
       500                                                                           20
              0       2002          2005    2010   2015   2020     2025     2030
                                                                                     0

                                                                 RENEWABLE ENERGY FOR EUROPE - RESEARCH IN ACTION

Professor N Cheung, U.C. Berkeley                                                                                46
EE143 F2010                                                Lecture 26




     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 ?
Professor N Cheung, U.C. Berkeley

								
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