Bias sputtering and characterization of LiCoO2 thin film cathodes for thin film microbattery

LiCoO2 thin films, which could be used as a cathode material in microbatteries, have been deposited by radio-frequency (rf) magnetron sputtering with various substrate biases as process parameter. The substrate bias during deposition has influenced the electrochemical properties of thin film electrode, and it could be found by charge–discharge test and cyclic voltammogram. We could obtain LiCoO2 thin film cathodes, which can be used directly, without annealing, for the complete thin film battery. The variations of electrochemical properties with substrate bias are related to micro-structural changes due to the ion bombardment, which delivers energy to the growing film. The bias sputtering of LiCoO2 is suggested as the promising method to fabricate thin film microbatteries.