**3.4 Impurities in the recrystallized silicon film**

The relatively high chlorine and hydrogen concentrations in the order of 0.5at% lead to outgassing during the recrystallization in completely melting regimes. This effect makes the capping layer arch upwards and widens the voids. Isolated pinholes in the silicon film can be observed. A weak hydrogen chloride peak is detected by mass spectrometry in the base gas atmosphere of the recrystallization chamber. Fig.11 shows an area surrounding a pinhole taken with SEM and the relative element concentrations measured by energy dispersive x-ray analysis (EDX) along the black line. There are no chlorine and hydrogen in the area surrounding a pinhole in the recrystallized film.
