Local anodic oxidation kinetics of chemical vapor deposition graphene supported on a thin oxide buffered silicon template

Study of local anodic oxidation (LAO) of single layer graphene (SLG) supported on thin oxide buffered silicon template is reported. Centimeter scaled SLG sheet grown through chemical vapor deposition on Cu foil is transferred onto patterned silicon template covered with thin oxide steps. LAO are performed on the supported SLG through contact mode atomic force microscopy in ambient condition. LAO bumps with heights exceed physical carbon-oxygen stacking are formed on thin oxide buffered samples. Micro-Raman spectroscopy reveals the coexistence of surface graphene oxide formation and local strain near the LAO patterns. The writing speed dependence of LAO bump shows a multi-exponent behavior, indicating inhomogeneous chemical profiles involved in the LAO process. The observation points to a sequential kinetics of surface SLG oxidation prior to subsurface silicon oxide protrusion formation. Our work shows the necessity to consider oxidation of substrate through the subsurface buffer layer during nano-scaled field effect device fabrication with LAO method. The strain generation from the subsurface protrusion suggests possible tuning knob for local distortion of SLG structure.