Study On Defects Of SiO₂/4H-SiC(0001) Interface By XPS

SiC power devices are the foreland of power devices field, MOSFET is an important partof power devices. Channel mobility of the actual SiC MOS is relatively low. Obtaining highquality oxides grown on SiC is a crucial step in realizing SiC MOSFET devices. Althoughgreat efforts on technics have been made to produce high quality SiC MOS interfaces inrecent years, the SiO₂/SiC interfacial defects aren't still well understood.This thesis systemically studies SiO₂/4H-SiC(0001) interface prepared by high-temperature oxidizing technic from chemical compositions, distributing of components,microstructures and so on using XPS which is suitable to elucidate structures and chemicalbond of SiO₂/4H-SiC(0001) interface, associating with the highly precise means to obtainsamples covered with the ultrathin oxide and "standard samples method" which enhances theanalytic reliability. The results indicate that the high-temperature oxidizing makesSiO₂/4H-SiC(0001) interface receive more carbonic leftover. What's more, Si²⁺ and Si³⁺ arefound besides Si¹⁺ which is usually produced when SiC is oxidized below 950℃. The resultsof ADXPS's testing suggest one layered model is suitable for describing the distributing ofcomponents at SiO₂/4H-SiC(0001) interface. The transition region's thickness of the samplereceived ROA, which is obtained by TPP-2M formula and intensity ratio equation, iscompared with the one of the sample not received ROA. And the comparison's resultindicates that ROA technic can make the transition region of which thickness doesn't exceed1nm observably thinner. The change of the transition components' quantum which is arousedby different technics and the interface state suggests that the quantum reduce of transitioncomponents results in the improvement of technics' efficiency. According as all theexperimental results, a interfacial microstructure model combining the near-interface-oxidemodel and the "Carbon Cluster Model" is put forward, showing atomic state, structure andspecies of defects at SiO₂/4H-SiC(0001) interface.By studying SiO₂/4H-SiC(0001) interface and its change after anneal techics, this thesisclears the structure of SiO₂/4H-SiC(0001) interfacial defects. What's more, the forms ofinterfacial defects, microstructural model and interfacial defects' effect to interface states arelucubrated, providing necessary theory basises for improving techincs and SiC MOSFET'sperformance.