Direct-Aluminum-Heating-Induced Crystallization of Amorphous Silicon Thin Film

Abstract

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 200-nm-thick amorphous silicon (a-Si) thin film with a size of 1 cm × 1 cm can be crystallized into a polycrystalline silicon (poly-Si) thin film within a few tens of seconds. The Raman spectrum analysis shows a peak of 520 cm-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 820 K.