Metal/high-k gate dielectrics stack structures for LSIs and metal/transition-metal-oxides (TMO)/metal structures for resistance random access memory (ReRAM) have been analyzed using synchrotron radiation nano-spectroscopy from the viewpoint of interfacial chemical and electronic states. We have developed a scanning photoelectron microscope (SPEM) with an angle-resolved electron analyzer and succeeded in obtaining chemical-state- resolved images and pin-point in-depth profiles of LSI gate patterns with 70 nm lateral resolution. For ReRAM, chemical-state-resolved images of Cu for a planar-type Pt/CuO/Pt resistance switching (RS) device revealed conductive filaments in TMO using photoelectron emission microscope (PEEM). Furthermore, in and out diffusion phenomena of oxygen corresponding to bias polarity for RS were observed for Pt/TaO x/Pt switching devices. Interfacial redox reactions which are common to all ReRAM devices are also observed for Al/TMO interfaces.