Berlin 2005 – scientific programme

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DS: Dünne Schichten

DS 19: Schichtabscheidung

DS 19.3: Talk

Tuesday, March 8, 2005, 14:45–15:00, TU HS107

Physics of the formation of polycrystalline silicon thin films by aluminum-induced layer exchange — •Jens Schneider, Juliane Klein, Andrey Sarikov, Martin Muske, Stefan Gall und Walther Fuhs — Hahn-Meitner-Institut Berlin, Kekuléstr. 5, 12489 Berlin, Germany

Polycrystalline silicon (poly-Si) thin films on foreign substrates are of great interest for large area electronic devices such as solar cells. Recrystallization of amorphous silicon (a-Si) is one approach to achieve such films. The use of in-expensive substrates like glass limits the process temperature to below the glass softening point at around 650^∘C. Solid phase crystallization (SPC) at these low temperatures is very slow and thus alternatives are searched for. Metals in contact with a-Si have been shown to reduce crystallization times. In metal-induced crystallization (MIC) silicide and non-silicide forming metals are distinguished. The use of Al (non-silicide forming) allows for an aluminum-induced layer exchange (ALILE) process. In ALILE a-Si/Al bi-layers are annealed below the eutectic temperature of Si and Al. The layers exchange position with a concurrent crystallization of silicon.

Here experimental results giving insight into the physics of the layer exchange are presented. The role of the initial a-Si/Al interface as well as the temperature influence is elucidated and their interaction explained. The process is discussed in the phase diagram. Classical nucleation theory is used to interpret the results.