Silver-rich GeTe solid electrolytes for use in programmable metallization cell (PMC) memory devices were prepared by the in situ diffusion of silver into the GeTe films during the deposition of silver by rf sputtering on GeTe chalcogenide glass films. The concentration of silver in the silver-rich GeTe films was controlled by adjusting the concentration of Te in the GeTe films. A PMC memory device with a Ag(300 nm)/Ag-x(Ge45Te55)(1-x)(200 nm)/TiW(100 nm) structure and a device diameter of 0.5 mu m showed reproducible memory characteristics based on. resistive switching at low voltage with high R-off/R-on ratios. The PMC memory device exhibited good switching characteristics up to 100 cycles at an amplitude of +/- 2 V and a pulse width of I mu s. (c) 2006 American Vacuum Society.