IntegRex - process development of a module interconnection concept for thin crystalline silicon films

In this work the realization of a concept for integrated interconnected crystalline silicon thin film solar cells in a laboratory process is described. This module concept, referred to as IntegRex (Integrated interconnection of recrystallized silicon layers), is developed for recrystallized or lift-off crystalline silicon layers. Following the classical thin film approach the crystalline silicon thin film is divided into individual cell strips and interconnected monolithically on a substrate. To investigate the individual processing steps silicon on insulator (SOI) wafers with a buried oxide layer and epitaxially deposited back surface field (BSF) and base are used instead of recrystallized or lift-off crystalline silicon films. A first batch of IntegRex mini-modules on SOI wafers was processed. Despite a not yet optimized metallization scheme, a VOC of over 3 V could be reached for a mini-module consisting of five cells. Problems that occurred in the metallization process are presented here and a possible solution is discussed.