Comprehensive Characterization of Advanced Cell Concepts with Sub-Micron Resolution

We introduce a comprehensive characterization approach of microscopic technological structures in advanced silicon cell concepts. Micro-photoluminescence spectroscopy and micro-Raman spectroscopy with their submicron resolution potential are applied, which allow a direct extraction of the most important parameters. These parameters are the micron resolved carrier lifetime, the doping density and the stress induced by the process. This paper covers exemplary measurements, which demonstrate the potential of this characterization approach for process optimization, details on the measurement techniques and on the sample preparation. The structures under test are laser doped back surface fields, nickel-plated contacts, back contact structures and epitaxial layers. The presented characterization techniques are able to reveal microscopic flaws in the technological structures and thus, allow for a direct and target-oriented optimization of the investigated processes.