Surface analyses of polycrystalline and Cz–Si wafers

Abstract

The performance of photovoltaic devices is greatly influenced by the surface characteristics such as surface roughness and presence of organic contaminants; therefore, their measurement is of great importance for photovoltaic industry. Moreover, these parameters should be measured by non-contact, fast methods capable of application as in-line techniques in photovoltaic industry. Surface roughness measurements and detection of organic contaminants by work-function measurements are the subject of this contribution. Monocrystalline and multicrystalline silicon wafers have been analyzed by Scanning Kelvin Probe (SKP ) in order to obtain work-function maps. These presented regions of higher work-function values correspond to organic contaminants, which are deliberately deposited on the wafer surface. In this way we have demonstrated the capability of work-function measurements for the detection of the contaminants. Moreover, unintentional organic contamination has been detected on multicrystalline Si wafers by SKP analyses. At the same time, the surface roughness has been obtained from surface topography maps.