Inline Sputter System for ITO and Ag Deposition on Heterojunction Solar Cells
One main-focus during solar cell production is on efficiency. Heterojunction cell technology (HJT) achieves conversion efficiencies of more than 22 % as well as reduced manufacturing costs. The newly developed GENERIS PVD system is a horizontal inline sputter tool designed for the special needs in photovoltaic high efficiency cell production.
Heterojunction cells are coated on both sides with transparent, conductive oxide (TCO) layers by PVD (physical vapor deposition). The system is ideally suited for challenging layer stacks i.e. transparent conductive oxide layers like ITO and AZO providing maximum optical transmittance, matched refractive index and optimum electrical conductivity as well as charge carrier mobility, which are key-parameters in heterojunction cell technology. Sputter damage to the amorphous silicon layer stack does not occur. Full substrate temperature control during the whole process enables optimum layer performance at temperatures ≤ 200 °C.
With the GENERIS PVD sputtering system, contact layers can be deposited on the front and rear of the wafers without the need to turn the wafers between coating processes and without vacuum interruption. Annealing of sputtered layers is integrated optionally. Finally full area metal coatings, e.g. Ag can be deposited within the same system. By using cylindrical sputtering magnetrons, high target utilization is achieved and offers lowest cost of production.
Other typical applications include anti-reflection layers, barrier layers and precursor layers, but also different metallic layers like Al, Cu, and NiV. The system is using an inline process in which the substrates are transported on specially designed carriers, providing edge isolation simultaneously. The carrier return system is located below the machine under clean environment conditions. Different automation options for loading and unloading are available.
Typical Performance Characteristics GENERIS PVD
- For transparent conductive oxide layers like ITO and AZO, e.g. for HJT
- Parallel processing of several substrates
- Throughput scalable from 2400 w/h – 5600 w/h
- Modular configuration
- Low cost of ownership and high uptime
- Top down and bottom up sputtering configurable
- Sputter sequence configurable
- Full temperature control throughout the whole process
- Rotatable cylindrical magnetrons for highest utilization of target material
- Sputtering materials: ITO, AZO and metals like Ag, Ni, NiV, Cu, Al, etc.
- Single end and double end version selectable
- Manual or semi-automated versions GENERIS Lab on request