The deposition of thin-film electrolytes is a critical step in the development of lithium microbatteries with the potential for circuit integration. We have performed a preliminary study of the radio frequency-magnetron sputtering of (1 - x)Li4SiO4:xLi3PO4 targets used to deposit amorphous thin-film electrolytes formed of the three-component system Li2O-SiO2-P2O5. Mass and optical emission spectroscopies have been used to investigate the effects of target composition and the deposition conditions upon the atomic and molecular species ejected from the targets. The data provide important information for understanding the mechanism of film formation and for monitoring the Li atomic flux onto the substrates during film growth.