Texturization of polycrystalline silicon films using excimer-laser processing for memory device applications

We report the first systematic investigation of texturizing polycrystalline silicon films utilizing an excimer laser to achieve an increased cell capacitance for high-density memory-device applications. The degree of surface roughness after laser processing was found to be sensitive to polycrystalline silicon deposition temperature and laser fluence. In the laser-fluence range of 0.2 to 0.7 J/cm2, the reflectivity of polycrystalline silicon films varied from ∼10% to 80%. A significant increase in the degree of surface roughness was achieved at optimized conditions. This, in turn, resulted in an increased effective surface area of the polycrystalline silicon film used as the capacitor-storage node. Primary capacitance-voltage measurements indicated a 10% increase in the cell capacitance, and current-voltage characterizations showed no device degradation due to laser processing.