Berlin 2005 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 64: Photovoltaik II

HL 64.4: Vortrag

Mittwoch, 9. März 2005, 11:30–11:45, TU P-N202

Comparison of dopant sources for laser doped crystalline silicon — •M. Ametowobla, A. Esturo-Breton, J.R. Köhler, and J.H. Werner — Institut für Physikalische Elektronik, Universität Stuttgart

Laser doping of crystalline silicon is a fast and effective method to produce abrupt pn-junctions with one side being highly doped. This approach replaces furnace diffusion for the emitter fabrication of crystalline silicon solar cells. For this purpose we deposit phosphorous and boron containing liquid doping precursor layers by spin on, spray on, roll on and inkjet processes. Alternatively, we investigate sputtering of boron or phosphorous atoms onto the silicon surface to obtain precursor layers. The deposition method and laser processing parameters affect dopant concentration and homogeneity, as well as junction depth. Junction depth depends mainly on the laser energy density, whereas doping efficiency is mostly influenced by the effective dopant concentration in the precursor layer and its thickness. Consequently, sputtered precursor layers result in the highest dopant concentrations, and require less laser energy than liquid precursor layers.