Lithium phosphorous oxynitride ͑Lipon͒ films were deposited in N 2 gas atmosphere with different radio-frequency magnetron sputtering power from 80 to 160 W with 20 W step increase. Lipon films deposited at lower sputtering power showed higher ionic conductivities than the films deposited at higher sputtering power. The results of impedance measurements showed that nitrogen incorporation into the glass structure increased the ionic conductivity and this nitrogen content in the Lipon films increased as the sputtering power decreased. In addition, the Auger electron spectroscopy depth profile showed that the increased nitrogen content in the Lipon films was not the result of the target surface poisoning effect but the result of reactive incorporation of nitrogen. The miniaturization of electronic devices has resulted in very low current and power requirements for many applications ͓comple-mentary metal oxide semiconductor ͑CMOS͒ CMOS back up, smart cards, implantable medical devices, microelectromechanical system ͑MEMS͔͒. Microenergy sources must be developed to drive these small electronic devices. A thin film battery ͑TFB͒ is one of the options for satisfying this demand. To make the thin film battery, a thin film solid electrolyte is indispensable.Solid electrolytes have several advantages over liquid electrolytes, such as no leakage problem, broad operating temperature range, excellent charge-discharge cyclic properties due to a lack of side reactions occurring and only one type of carrier ion migration, and long life because of little self-discharge. Such solid electrolytes should have properties such as a very high ionic conductivity, negligible electronic conductivity, and a very low activation energy.Ion conducting glasses are generally composed of three components, a network former, a network modifier, and a doping salt. The absence of structural constraints allows easy modification of their relative contents to optimize electrical and electrochemical properties. They are usually made by conventional melt-quenching.Based on this theory, several solid electrolytes were studied such as Li 2 S-P 2 S 5 -LiI, 17 Among these, Li 2 S-based solid electrolytes are unstable in contact with Li metal used as an anode and also unstable in atmosphere, although they show high ionic conductivities. On the other hand, while Li 2 O-based solid electrolytes are easy to handle in atmosphere, they show low ionic conductivities and the stability problem with Li metal contact is not solved.Recently, a new Li ϩ ion conducting solid electrolyte lithium phosphorous oxynitride ͑Lipon͒ was developed and has been successfully incorporated into rechargeable thin-film lithium batteries by Oak Ridge National Lab. 18,19 This material is stable with Li metal, easy to handle in atmosphere and shows high ionic conductivity. This amorphous material is deposited by sputtering Li 3 PO 4 in N 2 gas, and its composition can be represented by xLi 2 O:yP 2 O 5 :zPON, where PON is phosphorus oxynitride. Lipon films prepared in this way show high io...