Simultaneously high thermal stability and low power based on Cu doped GeTe phase change material
The resistance as a function of temperature (R ～ T)was measured in situwith a ramp rate of 5 °C min?1 invacuum chamber by a Pt-100 thermocouple located at a heating stage controlled by a TP 94 temperaturecontroller(Linkam Scientific Instruments Ltd, Surrey, UK). The 10-year data retention was estimated byrecording the isothermal change in resistance with elevated temperature. The UV–vis-NIR spectrophotometerwas used to measure the diffuse reflectivity spectra of the materials(7100CRT, XINMAO). The structure of thematerials was characterized by x-ray diffraction (XRD, D/max2550VB3)with the diffraction angle range of 20 to60°. X-ray photoelectron spectroscopy (XPS, Thermo ESCALAB 250XI) measurements with AlKa radiationwere employed to confirm the atomic percentage and the bonding situation of each element for GeTe andGeTeCu. The surface roughness of the materials was evaluated by atomic force microscopy (AFM, FMNanoview 1000), which was carried out in the semi-contact mode. The T-shaped PCM device cells with a 50 nmthick thin film was fabricated using photolithography process, and then and ～200 nm Al top electrode wasdeposited above the phase change material in sequence. The PCM devices based on Ge40Cu20Te40 materials werefabricated and the electrical switching property was measured by a Tektronix AWG5012B arbitrary waveformgenerator and a Keithley 2400 m.