Evaluation of Al(Nd)-alloy films for application to thin-film-transistor liquid crystal displays

Abstract

Higher-resolution, larger-diagonal active-matrix liquid crystal displays (AMLCDs) will require the use of low-resistivity gate metal such as aluminum transition-metal alloys. Al(Nd ≧ 3 wt.%) alloy films are adequate for AMLCD fabrication because of their low resistivity and their tendency not to form hillocks during thermal processing. The use of both optical light scattering and nanoindentation for the rapid evaluation of hillock formation has been demonstrated, along with the use of ramped resistance measurements for observing the process of discontinuous precipitation (the combination of Al grain growth and Al-Nd compound precipitation). Al(Nd) films were further characterized by TEM and AFM to confirm the effect of their finely dispersed Al-Nd compound precipitates on decreased grain size and decreased hillock formation.