Dresden 2011 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 85: Poster Session II

HL 85.75: Poster

Donnerstag, 17. März 2011, 18:00–21:00, P4

Thickening of polycrystalline silicon layers by solid phase epitaxy — •Ingmar Höger, Annett Gawlik, and Fritz Falk — Institut für Photonische Technologien, Albert-Einstein-Str. 9, D-07745 Jena, Germany

Crystalline silicon solar cells on glass substrates are considered to be an alternative to well established wafer-based concepts due to their potentials for cost reduction. This work deals with a seed-layer approach to obtain thin silicon films. First of all an amorphous silicon layer is deposited on bare glass substrates. Diode-laser crystallization by means of continuous-wave irradiation results in grain diameters of 100 µm. Next, the absorber gets deposited by high rate electron beam evaporation which needs to be crystallized via solid phase epitaxy in a tube furnace at temperatures around 600 ^∘C. In this way the crystallographic information of the seed-layer can be transferred to absorbers up to 1,5 µm in thickness. The maximum thickness is limited by the onset of nucleation in the amorphous material beginning after a certain retardation time and leading to crystallites several micrometers in seize. The kinetics of the solid phase epitaxy strongly depends on crystallographic orientation, doping concentrations and the a-Si preparation conditions. In order to prevent the formation of defects the interface between seed and absorber layer needs to be clean as well.