LPICM slides for WP3

Wanghua Chen and Pere Roca i Cabarrocas

2015-07-15

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Large scale epi-PECVD

confidential

156 ×156 mm

Thickness: ÅUniformity: 15.3 %Max: 51000Mean: 44103Min: 37457

Will be sent to Obducat for NIL;D 2.6

Thickness mapping by ellipsometry

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Investigation of peel-off of c-Si thin film during lithography

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Al

µc-SiOx

Epi-PECVD

First path: insertion buffer layers of ZnO and Ag

ZnO

Ag

Glass

SiSi

ZnO

Al

Agglass

glass

Detachment at large scale would be difficult

Increase of interface from two to fiveRisk of peel-off of each interface

Contrast-based image

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Second path: change the metal deposition technique

c-Si Al (1 μm)

ZnO:Al (80 nm)

Al (1 μm)

µc--SiOx:H (60 nm)

No peel-off for both samples

ObducatTest of resist

of NIL

Why ?

Thermal evaporated Al as compared to e-beam evaporated Al before

Investigation of peel-off of c-Si thin film during lithography

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Transfer epi-PECVD (5 µm) without ZnO

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Samples are ready except ITO and metallization

Waiting for ITO deposition (sputtering is out due to the broken of transfer arm and gas maintenance)

Bubble incorporated during Anodic bonding

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24 epifree with p-µc-SiOx are ready

Application of SiOx µc-SiOx as passivation buffer layer

What’s next stack on µc-SiOx ?Al from LPICM?

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Low deposition temperature: 200 ˚CHigh deposition rate: 1 nm/s

Flat Si

Pyramids with SiOx (Rave: 4.6 %)SiOx on glass

Pyramids

Deposition on large scale (156 × 156 mm) is realized

Application of SiOx: Front side passivation and ARC

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Simulati on of ARC on Si with random pyramids (SiOx vs SiCx vs SiNx)

Si (180 µm)

air

ARC

Jsc (mA/cm2)

SiOx Al2O3/SiCx SiNx

T (˚C) < 200 > 350 > 300

Reflected 1.18 0.79 0.76

Absorption(ARC)

0.00 0.52 0.39

Absorption (Si)

42.82 42.70 42.85

OPAL modelling

Benefits of SiOx: low temperature process

1 μm

SEM contrast-based colorful image

Conformal coating of SiOx on pyramid structures

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Application of SiOx Buffer layer for laser scribing of IBC

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Laser: 355 nm

Index n;Thickness;

n

ip

c-Si

laser

Laser-induced defect

Laser power

HF removal of μc-SiOx

μc-SiOx Laser power

HF removal of μc-SiOx:1 secs to 5 min depending on

porosity and Si fraction

Imec slides for WP3

M32, June 15th

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Done and planned at imec

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D3.3 report Finished and submitted to EC! Next deliverables: D3.4 (HCL cells) and D3.5 (record)

Anodic bonding Done on PECVD-Si samples

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Epifree record cellsWhat to do?

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Samples sent to LPICM for uSiOx

And then? to be determined...Rear:

with ZnO to improve adhesion? with Ag or only Al?

TextureNIL: dry vs. wetHCL?E-beam?

Emitter standard a-Si:H or a-SiOx? Or thinner a-Si:H?

Chalmers slides for WP3

M32, June 15th

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Task: Check that wafers after wet-HCL keep a reasonable lifetime for cell processing to re-do the lifetime measurements performed on IM93

Batch IM109 – 4 inch wafers10 samples + 2 reference samples

D3.4 Second batch of cells with non-periodic optimal patterns

Cleaning O2 plasma PS self-assembly Mask Wet etch

2 samples 2 samples 2 samples 2 samples 2 samples

Samples processed and sent to IMEC to be etched (2 samples) and passivated (all samples)

nanophotonics for ultra-thin crystalline silicon photovoltaics

This project has received funding from the European Union’s Seventh Programme for research, technological development and demonstration under grant agreement No 309127