PURIFICATION AND HYDROGENATION OF METALLURGICAL SILICON POWDER BY RF THERMAL PLASMA. CHARACTERIZATION OF THE DEPOSIT

摘要

Plasma deposition process of metallurgical grade silicon powders was used in order to combine purification and deposition processes onto different kinds of substrate with a high deposition rate ( ≈ 100 μm.mn~(-1)). The particles are heated, melted, partially vaporised and finally deposited on a substrate. Under optimised experimental conditions dense deposits are obtained on ceramic substrate with a thickness close to 1 mm. Except the final crystallised zone, EDX and ICP analysis show that the deposits have good purity. However, because of a fast crystallisation, several crystalline defects have been observed. Introduction of hydrogen was used in order to passive this defects and to increase the photovoltaic properties.