Direct aluminum heating induced crystallization of amorphous silicon thin film

In this research, a novel direct aluminum heating induced crystallization method was developed for the purpose of application to solar cells. By applying a constant current of 3 A to an aluminum thin film, a 200nm thick amorphous silicon (a Si) thin film with a size of 1cm x 1cm can be crystallized into a polycrystalline silicon (poly Si) thin film within a few fens of seconds. The Raman spectrum analysis shows a peak of 520cm'-1', which verifies the presence of poly Si. After removing the aluminum layer, the poly Si thin film was found to be porous. SIMS analysis showed that the porous poly Si thin film was heavily p doped with a doping concentration of 10'21'cm'-3'. Thermal imaging shows that the crystallization from a Si to poly Si occurred at a temperature of around 820K