Low-cost Cu-plated metallization on TCOs for SHJ Solar Cells - Optimization of PVD Contacting-layer

Hydrophobic AlOx Surfaces by Adsorption of a SAM on Large Areas for Application in Solar Cell Metallization Patterning

“…SHJ solar cells with a Al/AlO x mask were already presented, allowing to reach the same order of efficiencies with a high fill-factor FF. 22 Figure 1 illustrates the complete adapted NOBLE processing sequence. A PVD tool was used to deposit the metal stack on ITO followed by ALD deposition of Al 2 O 3 on top (a).…”

“…Plated metallization is commonly performed by applying an organic resist 13−17 or dielectric layers 15,16,18−21 as a plating mask. Recently, another low-cost 22 approach based on self-passivation of an aluminum layer as a plating mask 23 has been developed (see the adapted sketch in Figure 1). In this metallization approach called native oxide barrier layer for selective electroplating, i.e., NOBLE metallization, selective copper electrodeposition is achieved on a patterned physical vapor deposition (PVD) metal-seed over the Al/native AlO x masking layer (Figure 1c).…”

“…This layer stack may not be ideal for actual solar cell manufacturing, and the adhesion of Cu to ITO is relatively low, as shown in the literature. 22,44 However, this layer stack can still be attractive for other applications without the use of ITO. Also, optical characterization is simplified by this sample design.…”

“…Also, optical characterization is simplified by this sample design. The other SHJ solar cells were covered on both sides with 5 nm Ti (promoting adhesion 22 ) and 100 nm Ag (500 nm on rear) by thermal evaporation with edge exclusion due to the limited tool size. The silver layer was then covered with evaporated Al (50 or 70 nm) or a different thickness of plasma-assisted ALD-Al 2 O 3 (FlexAL from Oxford Instruments) at 180 °C (7, 12, 19, and 23 nm).…”

Multifunctional Titanium Oxide Layers in Silicon Heterojunction Solar Cells Formed via Selective Anodization

“…[ 14 ] The layers below the TiO x , are protected from the chemical liquids used for plating, etching, and anodizing as the process is based on oxygen and titanium ion movement through the solid material; and 3) The challenging selective wet etching step of the Ti layer, when Ti is applied in the standard NOBLE process as an adhesion layer, is replaced by the anodization step. Therefore, the application of hazardous chemicals for selective chemical etching of the Ti [ 15 ] is avoided and the process route remains lean, as no additional process step is required.…”