Explotation And Verification Of Control Module Contained In Epitaxial Graphene Fabrication System

Graphene has a wide application in national defense and economy due to its outstanding electronical properties.However,it is hard to fully use those advantage of graphene in industrial applications,the current research show that the nanoelectronic properties of graphene can be integrated in large areas only when the appropriate substrate is attached,and high quality large size graphene sheets can be obtained.Epitaxial growth of graphene on Si C is considered to be a ideal way to achieve large scale integrated circuit.Therefore,how to prepare a large area full wafer SiC-based graphene material quickly and well becomes a problem to be solved.In this study,epitaxial growth of wafer level graphene on SiC is investigated experimentally and theoretically centreing on the process method and characterization technology.It is hoped to fabricate high quality graphene material via optimizing technique of the hydrogen etching and growth with the consideration of cost.In order to meet the conditions required for epitaxial growth,the control system of the equipment was studied.The specific research content is as follows:?1?The high precision requirements of the epitaxial graphene for gas flow,pressure,and temperature,the epitaxial preparation system is integrally constructed,and the epitaxial working system,gas supply and gas transmission system,exhaust gas treatment,and safety system have been researched and improved.The improved control system realizes precise control of gas flow,pressure and temperature,ensures uniform and stable gas flow,pressure and temperature obtained from the epitaxial material on the sample table,and uses different schemes for different kinds of exhaust gas generated during the growth process.The treatment,and for each dangerous gas is equipped with an alarm,and explosion-proof exhaust fan,to ensure the safety of the experimental process.To lay the foundation for follow-up research.?2?In order to remove mechanical scratches and defects on the surface of the substrate and provide good substrate conditions for subsequent epitaxial growth,the hydrogen etching process was investigated experimentally.Experimental studies have found that temperature and etching time have different effects on the etched surface:changes in temperature have a great influence on the etch rate;faster etch rate can remove deeper pit defects in the step;Etching time and the width of the step is positively correlated,and the width of the step can be controlled by controlling the etching time.Finally,etching was performed at1600?and 100 mbar for 30 seconds to obtain an etched surface where the steps were substantially uniform and the step height was 2 nanometers and the width was 2 micrometers.?3?Aiming at the problems of high temperature and vacuum requirement and long growth time for physical sublimation method,a new idea was proposed.HCl was used to extract Si atoms in SiC and trace amounts of C₃H₈ were added to assist graphene film reconstruction.We conducted an experimental exploration of the growth parameters?pressure,temperature,HCl/propane gas flow,duration?of this new method.The atomic force microscopy test found that the surface has a regular step-like morphology.Through Raman test characterization found that the presence of carbon film in some areas,which also provides an experimental demonstration of another possible solution for epitaxial growth of graphene silicon carbide.?4?For the existing high temperature,ultra-high vacuum manufacturing poor control of thickness,and growth of epitaxial graphene,put forward a more superior preparation program,under low vacuum epitaxial graphene grows and Ar is used as a filling gas.After characterization of the material by light microscopy,atomic force microscopy,and Raman measurement techniques,it was found that a quasi-free,high-quality,large-area single layer was grown on the carbon surface of a three-inch substrate by reducing the degree of vacuum in epitaxial growth.