Low temperature strain behavior of Pb thin films on a substrate

摘要: The microstructural changes occurring during cooling from 300 to 100 K in a 0.2 μm thick polycrystalline Pb film deposited on Si3N4 substrate were studied by combination of transmission electron microscopy and X-ray diffraction technique. tensile strain induced the upon due thermal expansion coefficient mismatch between was observed be relaxed dislocation glide. Most dislocations glide across grains 111 planes that are inclined at an angle ∼ 70 deg surface, nearly parallel surface. All motions confined each grain surface oxide, substrate, boundaries. Some observations suggested these emanate At K, density introduced with diameters larger than ∼0.6 found roughly constant (about 1010/cm2), while no smaller μm. can account for amount which measured It also almost all events involved cycling process reversible. This explains previous result work hardening effect films low temperature. yield stresses as determined measurements about three times higher those expected simple pinning model. Based motion this work, re-evaluated function thickness size using energy criterion model took into effects oxide