Wet processes for conductive layer of silver and insulating layer Al2O3 for thin-film transistor

Dry thin film process involves complicated procedures and expensive equipments. In this study, wet processes using electroless deposition of silver (Ag) and electrophoretic deposition (EPD) of Al₂O₃ were realized. The result of Ag and Al₂O₃ layer on glass of TFT is presented. Since Ag exhibits low resistivity, it is selected to be the material of conductive layer. The electrical and mechanical properties of Ag thin film as a function of the deposition time and temperature were studied. Nano-scale Al₂O₃ powders with a mean particle size of 20 nm in diameter was prepared for the electrophoretic deposition to form an insulator layer. Various pH values from 1 to 10 were formulated to obtain colloidally stabilized electrophoretic suspensions. The concentration levels are set from 1.25 to 7.5 wt %; and the deposition time is set from 5~15 seconds to obtain stabilized depositions. After the electrophoretic process, the depositions of Ag and Al₂O₃ were sintered. Four-point probe, surface analyzer and Nano indenter were used to measure the electrical resistivity and mechanical properties of the depositions.