Anodization of Al–Nd alloy films in nonaqueous electrolyte solutions for TFT-LCD application

Abstract

The anodization behavior of Al–Nd alloys in nonaqueous electrolyte solutions and the electronic properties of the resultant anodic oxide films were studied for TFT-LCD application. Sputtered Al–Nd alloy films on glass substrates were anodized at 25 °C and 1 mA cm −2 up to 100 V in ethylene glycol–water solutions containing 10 wt.% ammonium tartrate or salicylate to give uniform and flat oxide films. The incorporation of organic components into the anodic oxide films from the electrolyte solutions has lowered the relative permittivity and increased the breakdown electric field of the oxide films. This was performed by decreasing the water content in the electrolyte solutions. The tartrate solution caused higher carbon incorporation than the salicylate counterpart at the same water concentrations, giving lower relative permittivity, and higher forward breakdown electric field. The AlO stretching frequency of the oxide films decreased slightly as the amount of incorporated organic moieties increased. Nd was uniformly distributed in the oxide films and an increase in the Nd content was likely to increase both the relative permittivity and the forward breakdown electric field without any apparent change in the anodization behavior.