NanoPERC – Industrial processes for nanocontacted poly-Si layers for a PERC successor technology with passivating contacts
In the NanoPERC project, a successor technology to the PERC solar cell will be developed. It will feature passivating contacts based on poly-Si with an efficiency of more than 23.5% and the necessary processes and equipment for industrial mass production. The desired cell structure replaces the current efficiency limiting phosphorus emitter of the PERC cell with a rear passivating n-type poly-Si contact. The p-type Si wafer and the passivation of the second side with an AlOx/SiNy layer stack are deliberately designed close to the current production for faster market integration of the cell. The cell process can be shortened by using a one-sided deposition of poly-Si. Therefore, the poly-Si layers are deposited with the innovative sputtering coating techniques. For this purpose, a suitable sputtering process must be determined and a thermal healing process developed with which the sputtered layers are converted into polycrystalline silicon with excellent passivation properties. The aim is to produce highly doped layers in a single step with targets suitable for industrial applications. In addition, a wet-chemical process for texturing, polishing, cleaning and oxidation with ozone is being developed in a single equipment. For this purpose, different process sequences and plant engineering challenges will be investigated. Using the developed wet-chemical and deposition processes, high-quality passivated n+-type contacts will be demonstrated. In addition, the corresponding equipment concepts for industrial implementation in inline operation will be developed for these processes. Moreover, a new front metallization design is being developed for module integration. These cells will then be used to produce a module with an efficiency of 22%.
Duration of the project
01.05.2019 – 31.08.2022
The project “NanoPERC – Industrial processes for nanocontacted poly-Si layers for a PERC successor technology with passivating contacts” is funded by the Federal Ministry of Economic Affairs and Climate Action under grant number 03EE1012A. Responsibility for the content of this publication lies with the authors.