Polycrystalline Si layers were prepared by interference laser crystallization in the superlateral growth regime. To characterize their microscopic photoelectrical properties, light beam induced current was used, employing a focused laser beam for local

generation of photo-carriers in the layers with spatial resolution of about 0.4µm. The results were correlated with surface morphology obtained by atomic force microscopy. In the single pulse interference laser crystallization, the temperature profiles were optimized by changing the proportion of interfering beam intensities. The typical grains were of triangular shape, with a length of 1.5 µm and width below 0.5µm. The photocurrent response was dominated by variations in the sample thickness. In the multiple pulse interference laser crystallization, thin films with grains of quadratic shape and of size exceeding 5µm were obtained by shifting the sample through an interference pattern, thus taking advantage of lateral epitaxial re-growth. Here, by use of a lock–in, light beam induced current methods could detect position and local electronic properties of individual grain boundaries. Grain boundaries were clearly identified by 180° shifts of the photocurrent phase close to maxima of photocurrent amplitude. The photocurrent was attributed to local fields at grain boundaries. These fields extend about 1.4µm into the grains. The barrier height at the boundary was about 110mV.

Laser Beam Induced Currents in Polycrystalline Silicon Thin Films Prepared by Interference Laser Crystallization. B.Rezek, C.E.Nebel, M.Stutzmann: Journal of Applied Physics, 2002, 91[7], 4220-8