Dresden 2009 – scientific programme
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DS: Fachverband Dünne Schichten
DS 3: Layer Deposition Processes
DS 3.2: Talk
Monday, March 23, 2009, 16:00–16:15, GER 37
Vapor--liquid--solid growth of silicon on glass — •Robert Heimburger1, Nils Deßmann1, Thomas Teubner1, Rainald Mientus2, and Torsten Boeck1 — 1Leibniz--Institut für Kristallzüchtung, Max--Born--Straße 2, D--12489 Berlin, Germany — 2OUT e.V., Köpenicker Straße 325, D--12555 Berlin, Germany
Development of low cost deposition techniques leading to high quality polycrystalline silicon films on glass is of great interest for solar cell industry. By taking advantage of growth from metallic solutions, vapor--liquid--solid processing promises both, cheap processing and good crystalline quality. In a first step, a liquid metallic solvent (indium) is deposited on glass, which was previously coated with thin conductive layers, to form well distributed microdroplets on the surface. These droplets act as nucleation sites for silicon deposited in a second step. Outgrowth of separated silicon seed crystals is done using specially adopted steady--state liquid phase epitaxy equipment [1].
One key factor for process development is the proper selection of backside contact material regarding thermodynamic stability, adhesion and wettability. Thermodynamic stability, i.e. the ability to withstand the silicon saturated solution during outgrowth, depends crucially on heat treatment during deposition process. Wettability is shown to be a function of deposition temperature, rate and surface pretreatment. Fully processed samples exhibit significant outgrowth of seeds into typically {111} faceted silicon crystals demonstrating the feasibility of the process.
[1] T. Teubner et al., Cryst. Growth Des. 2008 8 (7), 2484--2488