Amorphous lithium phosphorus oxynitride (UPON) solid-state thin-film electrolyte has been deposited and characterized. The thin films were prepared by rf magnetron sputtering under various substrate biases. By fabricating under different substrate biases and applying low temperature annealing (473 K), the properties of the LiPON thin-film electrolytes and the electrolyte/cathode interfaces were modified. The ionic conductivity as high as 9.4 X 10(-4) S m(-1) can be obtained by depositing at optimal bias. The performances of the consequently fabricated SnO2/LiPON/LiMn2O4 all-solid-state lithium ion thin-film batteries were improved using the bias sputtering technique, due to the enhanced the ionic conductivity and uniform interface. (c) 2010 American Vacuum Society [DOI: 10.1116/1.3435330]