LPICM slides for WP3 Wanghua Chen and Pere Roca i Cabarrocas

2 Large scale epi-PECVD confidential 156 ×156 mm Thickness: Å Uniformity: 15.3 % Max: Mean: Min: Will be sent to Obducat for NIL; D 2.6 Thickness mapping by ellipsometry

3 Investigation of peel-off of c-Si thin film during lithography confidential Al µc-SiOx Epi-PECVD First path: insertion buffer layers of ZnO and Ag ZnO Ag Glass Si ZnO Al Ag glass Detachment at large scale would be difficult Increase of interface from two to five Risk of peel-off of each interface Contrast-based image

4 confidential 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 Obducat Test of resist of NIL Thermal evaporated Al as compared to e-beam evaporated Al before Investigation of peel-off of c-Si thin film during lithography

5 Transfer epi-PECVD (5 µm) without ZnO confidential 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

6 confidential 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?

7 confidential Low deposition temperature: 200 ˚C High deposition rate: 1 nm/s Flat Si Pyramids with SiO x (R ave : 4.6 %) SiOx on glass Pyramids  Deposition on large scale (156 × 156 mm) is realized Application of SiOx: Front side passivation and ARC

8 confidential Simulation of ARC on Si with random pyramids (SiOx vs SiCx vs SiNx) Si (180 µm) air ARC Jsc (mA/cm 2 ) SiOxAl2O3/SiCxSiNx T (˚C)< 200> 350> 300 Reflected Absorption (ARC) Absorption (Si) OPAL modelling  Benefits of SiOx: low temperature process 1 μm SEM contrast-based colorful image Conformal coating of SiOx on pyramid structures

9 Application of SiOx Buffer layer for laser scribing of IBC confidential Laser: 355 nm Index n; Thickness; n i p 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

11 Done and planned at imec confidential 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

12 Epifree record cells What to do? confidential Samples sent to LPICM for uSiOx And then? to be determined...  Rear:  with ZnO to improve adhesion?  with Ag or only Al?  Texture  NIL: dry vs. wet  HCL?  E-beam?  Emitter  standard a-Si:H or a-SiOx? Or thinner a-Si:H?

Chalmers slides for WP3 M32, June 15th

14 confidential 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 wafers 10 samples + 2 reference samples D3.4 Second batch of cells with non-periodic optimal patterns Cleaning O 2 plasma PS self- assembly Mask Wet etch 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