Trap-state density in continuous-wave laser-crystallized single-grainlike silicon transistors

Abstract

This investigation characterizes electrical characteristics of continuous-wave green laser-annealed single-grainlike silicon thin-film transistors in relation to trap-state densities. As laser power increases, highly crystalline channels form, reducing tail-state densities to as low as 3 X 10(19) eV-' cm(-3). This occurrence is responsible for high field-effect electron mobility of 284 cm(2)/Vs. In contrast, increasing laser power initially reduces the deep-state density and then increases it to 3 X 1016 eV(-1) cm(-3). This reversal in deep-state density and thus in the subthreshold slope as well as a saturating reduction in threshold voltage are associated with the formation of extra interface defects caused by laser-crystallization-enhanced surface roughness. (c) 2006 American Institute of Physics.