Fabrication of silver conductive lines by spray deposition method
Subject Areas : journal of New Materials
AliReza Ghahremani
1
(Department of Materials Science and Engineering, Shiraz University of Technology, Shiraz, Iran)
Ali Mashreghi
2
(Department of Materials Science and Engineering, Shiraz University of Technology, Shiraz, Iran)
Keywords: electrical resistance, Silver conductive line, Spray deposition,
Abstract :
Abstract Introduction: Silver conductive lines are used extensively in electronics and optoelectronics. These lines are deposited by different methods. In this work, silver lines were deposited by spraying diluted silver ink. Silver ink was synthesized by Lewis-Walker method. Then, it was diluted by ethanol for spray deposition. Since substrate is at high temperature, both the deposition and annealing are performed at one step. Methods: For synthesis, silver acetate, ammonium hydroxide and formic acid were used as silver source, stabilizing agent and reducing agent, respectively. Finally, the obtained ink was diluted by ethanol. Spray deposition was done with nitrogen using air brush. Findings: Different parameters were investigated. First, ink to ethanol volume ratio of 1 to 10 was determined as optimized value. It was observed that 60 cycles of spraying gives layer thickness of 3 μm. Substrate temperature of 180˚C was determined as optimized value. Scanning electron microscopic (SEM) image showed that deposition at 40˚C led to discontinuous layer with island-like microstructure and deposition at 280˚C led to porous plate-like microstructure. But deposition at 180˚C led to continuous layer. X-ray diffraction patterns showed that silver layers deposited at 40˚C have a mixture of silver acetate and elemental silver phases, but layers deposited at 180 ˚C and 280 ˚C have pure elemental silver phase. Conclusion: It was observed that low resistance silver layer can be obtained by spray deposition of diluted silver ink. The silver layer deposited at optimized condition showed resistivity of 1.4 × 10-7 Ωm.
