polysilanes: all-rounderbasematerialsin pv · unlessa polysilane-basedbulksi production,...

Polysilanes: all-rounder base materials in PV

City Solar Technologie GmbH & Co. KG Bitterfeld-Wolfen, Nov 15, 2007

© City SolarBitterfeld-Wolfen, 15.11.2007

Outline

•Introduction

•silanes as common base materials in PV

•polysilanes: potential all-rounders in Si-based thin film technologies

•conclusions


CITY SOLAR: LEADING PV POWER PROVIDER WITH STRONG TECHNICAL IN-HOUSE CAPABILITIES• Founded in 2003• Up-to-date: ~40 MWp projects completed• Revenue 2007 ~ € 170 millions• Core business

– Development, design, construction and operation of large scale PV power plants• Differentiators:

– Technology focus / R&D– Strong project development

PV power plant in Göttelborn/Germany (4 MWp)


SOME REFERENCES

PV power plant Sembach (Germany): 4 MWp.

PV power plant Saarbrücken (Germany): 4 MWp. Rooftop power plant Biberach (Germany): 1,5 MWp.

PV power plant Göttelborn (Germany): 4 MWp.


BENEIXAMA (SPAIN) – 20MWp

March 2007


BENEIXAMA (SPAIN) – 20MWptoday‘s LARGEST PV SOLAR POWER PLANT WORLWIDE

March 2007


City-Solar-modules “PQ 200“ in Beneixama (Spain / 20 MWp)

TECHNICAL COMPETENCE PROVIDES PERFORMANCE ADVANTAGE

• In-house experts select the best available products (inverters, transformers, etc.).

• City Solar module type (“PQ 200”) has already been successfully installed in several PV power plants (e.g. Sembach, Saarbrücken, Biberach, Lindau, Beneixama / Spain)

• With its in-house competency City Solar is able to guarantee life-cycle costs

Budget Actual 2006 in %kWh/kWp kWh/kWp

SB FH1 974 1.082 111%SB FH2 974 1.063 109%SB FH3 974 1.106 114%Sembach1 972 1.013 104%Sembach2 972 1.013 104%Sembach3 972 1.133 117%KH Herrenwald 974 1.077 111%KH Kurz 962 1.087 113%


COMPANY SET-UP

• project development• engineering• construction• Operation&Maintance

• Investment in powerplants

productionpartner

City Solar AG


CITY SOLAR OUTGROWS THE MARKET

0

50

100

150

2003 2004 2005 2006 2007 (FC)

Turnover in Mio. € Employees

CAGR 2003-2007: 326%

Target BU Power Plants• Gain market

share in a +20% p.a. growth market

è target > 50% p.a.growth until 2010

è City Solar in 2010 > € 800m revenue(w/o possible mega projects)


Overview: our technology portfolio

2. Silicon and TF precursor production

6. Tracker / mover

1. Power plantengineering

5. Concentratortechnology

3. Pure water 7. Mobile heat storage

4. ORC turbine 8. White Fuel / hydrogen onon demand


Silanes: base materials in PV

mg-Si

common Silanes in PV:

HSiCl3 „TCS“

SiH4 „Silane“

Siemens

FBR

FBR

Siemens

PECVD

a-Si/µc-Si PV modules

TFT, FPD

granular sg-Si

chunk sg-Si, eg-Si

granular sg-Si, eg-Si

chunk sg-Si, eg-Si

•also in use for TF-PV: HSiCl3, SiCl2H2, SiH4 (CVD precursors)

Silanes as common precursors for Si deposition: CVD thin film growth rate of typical gas phase precursors

The thermal decompositionproperties strongly dependon the number of substitutedCl atoms. Example: At ~850°C, SiH4 has a 50 times higher growth rate thanSiCl4.

reported for Si2Cl6at 450°C

reported for Si2Cl6at 850°C What happens, if the silane contains

more than on Si-atom in a Si-Si-bond?The Si-Si- bond breaks more easilythan a Si-Cl-bond – a huge influenceon the thermal decompositionproperties should be expected.This is exactly what isexperimentally observed !

Example: Si2Cl6, the „big brother“ of SiCl4


Polysilanes in TF technology

Si2H6 Disilane

less common „Poly“-silanes already in use in TF technology:

CVD

CVD

PECVD

Printing, coating a-Si, µc-Si TFT

Si, Si-C, Si-O, Si-N

a-Si, µc-SiSi3H8 Trisilane

Si2Cl6 Hexachlorodisilane

Si5H10 cyclo-Pentasilane

higher rate/lower T!

higher rate/lower T!higher deposition rate!a possible key towardscost reduction in a-Si/µc-Si tandem thin film PV, buttoo expensive

potentiallydisrupting newSi-coatingtechnology

Si3Cl8 Octachlorotrisilane

Si, Si-C, strained Si/Ge

today: 4000-7000$/kg

today: ~4000$/kg !

today ~25000$/kg !

?? $/kg

??? k$/kg

PRINTABLE ELECTRONICS

Liquid polysilanes as molecular precursors:

„enabling technology“ for

„Printable electronics“and „Electronic precursors“

liquid molecular precursor deposition/thermal processingExample (Seiko Epson 2006)


SI BASED PRINTED DEVICES CAN BE MADE

„Nature“, April 2006 Precursor: Cyclopentasilan Si5H10, dissolved in ToluolAuftrag: ink jet and spin coating

It has been shown already that silicon based devices can be produced from H-Silanes with ink jet or spin coating processes. This could revolutionize the production technology of many electronic devices, if it would be possible to produce the required amount of these silanes at competitive cost.

source: Seiko Epson 2006:


SIGNIFICANT COST SAVINGS BECOME POSSIBLE

source: Seiko Epson 2006

CS-Technology is capable of producing the required silanes at competitive costs


…TO AN ARRAY OF MULTI-GENERATION APPLICATIONS

SiO2

SiCl4

SinCl2n, SinCl2n+2

Derivatization

• coatings(SiC, Si3N4,SiOx)

• silicide layers • doped Si + Si/Ge

layers

Plasma technology

• Solar Silicon

• PV thin film• printable

electronics• alternative fuels

• New chemical compounds in industrial quantities

• The potential of our technology goes far beyond SG-Silicon: It turned out to be the key to numerous applications in the electronics, materials, and energy market with outstanding growth potentials

HydrationPyrolysis

FROM THE IDEA OF PRODUCING SOLAR SILICON…Laboratory micro wave, Frankfurt university, spring 2005

City Solar approach to Polysilanes

Polysilane, „PCS“

beyond oil

further

processing Silane

product

Multi cas-ting

mono Rib-bon

Thick film wafer subst.

a-Si TF

µc-Si TF

c-Si TF

Si-C Si-N H2 sto-rage /fuel

Cl-Oligosilanes TF precursors

gas phase and liquid phase

Raw PCS Granular poly-Si

Raw PCS Solid H-

Polysilane (HPS)

H-Oligosilanes n ≤ 8

TF precursors gas phase

H-Oligosilanes n ≥ 8

TF precursors liquid phase

Chl

oro-

Poly

sila

ne (P

CS)

feasibility

Common wafer-basedPV

TF-PV + electronics electronics

From a new solar Si production process……to a world of applications


The solar Si project


SiCl4 + H2 + energy → SinCl2n + SinCl2n+2 + HCl

SinCl2n + SinCl2n+2 + Δ → Si + SiCl4

1.Plasma polymerisation(T = Room Temperature)

2. Thermal decomposition (T >400°C)

City Solar process for SG-Si productionSG-Silicon production through pyrolysis (thermal decomposition) of chlorinated polysilanes.

Polysilane, „PCS“


FAST-TRACK DEVELOPMENT OF THE PLASMA-CHEMISTRY TECHNOLOGY

Q4/2005 Q1/2006 Q4/2006 Q4/2007

0,01kg/a

1kg/a

~50kg/a

~1,0t/a

~10t/a

yearlythroughput of a singleplasma system (in t Si)

@ 365/24/7

0

0,0001

0,001

1,0

10,0

Q2/2005

0,00001

0,01

0,1

target


October 2006: first successful production tests with the solar silicon of City Solar

Si project: the granular Si product

-Our granular Si can be melted with standardproduction technologies

-cells with City Solar Si admixture are as good as cells made from 100% standard Si

-poly Si wafers from100% City Solar Si are p-type withfollowing room temperature electrical properties:-resistivity of 4…4,5 Ohmxcm, -free carrier concentration p=5*1015 cm-3, -mobility µ ~ 300 cm2/(Vs)

-CZ single crystals grown (IKZ Berlin) from 100% City Solar granular Si. The material is p-type, 10 Ohmxcm. Further properties are under investigation (ISE Freiburg).


Polysilane portfolio from plasma PCS technology

Si2H6 Disilane

Readily available via Plasma-Polysilane technology:

Si3H8 Trisilane

Si2Cl6 Hexachlorodisilane

Many other isomers and derivates

Si3Cl8 Octachlorotrisilane

„PCS“

SinCl(2n+2) + SinCl2n

Si4Cl10, Si5Cl12,…

solid Cl-Polysilanes

Si4H10, Si5H12,…solid H-Polysilanes n>20

Today commercial precursor product

Today commercial product

Today commercial product

NEW precursor product

NEW precursor products





beyond oil

further

processing Silane

product

Multi cas-ting

mono Rib-bon

Thick film wafer subst.

a-Si TF

µc-Si TF

c-Si TF

Si-C Si-N H2 sto-rage /fuel

Cl-Oligosilanes TF precursors

gas phase and liquid phase

Raw PCS Granular poly-Si

Raw PCS Solid H-

Polysilane (HPS)

H-Oligosilanes n ≤ 8

TF precursors gas phase

H-Oligosilanes n ≥ 8

TF precursors liquid phase

Chl

oro-

Poly

sila

ne (P

CS)

feasibility

Common wafer-basedPV

TF-PV + electronics electronics

From a new solar Si production process……to a world of applications


PRODUCT PIPELINE SI – PLASMA - POLYMERS

HPS [SinH2n+2]; n>1

CPS [SinCl2n+2]; n>1

bulk siliconOligosilane

[SinH2n+2]; n = 2 - 8

liquid silane precursor

[SinX2n+2]; n =2-8

solid H-Silane[SinH2n+2];

n > 8

Si2Cl6

SiCl4

time-to-market ~ 1year ~ 1 year 1 – 2 years ~3 years > 3 yearsmarket PV electronics electr. & PV electr. & PV energy storage


Chlorinated Plasma-Polysilanes have been developed as a easy-to-decompose interstage product for bulk Si production and turned out to be all-rounders for low-cost thin film deposition.

A novel industrial polysilane production process was developed and successfully up-scaled.

The existing engineering of a bulk-Si Fab yields the up-scaling option for a multi-1000t/y, low cost production of high-performance precursors.

An impressive portfolio of liquid/gaseous precursors for many all functionallayers in electronics and PV becomes accessible.

Unless a polysilane-based bulk Si production, the start-up of a precursorproduction with a capacity of <100t/y PCS is possible based on today‘s maturepilot technology and with an affordable capital. It gives, however, a huge leverage towards >>100MWp/y of solar modules at highly competitive costs already.

Conclusion

polysilanes: all-rounderbasematerialsin pv · unlessa polysilane-basedbulksi production,...

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