Crack-release Transfer Method of Wafer-scale grown Graphene Onto Large-Area Substrates

Abstract: We developed a crack-release graphene transfer technique for fabricating graphene-based electronics devices. Graphene film grown on metal catalysts/SiO2/Si wafer should be scathelessly peeled for sequent transferring to a target substrate. However, when the graphene is grown on the metal catalyst on a silicon substrate, there exist a large tensile stress resulted from a difference of the coefficient of thermal expansion in the catalyst and silicon. The conventional methods of detaching graphene from metal catalysts were found to induce considerable mechanical damages on graphene films during separation process including metal wet etching. Here we report the new technique that bubbles generated by electrolysis reaction separates thin metal catalysts from SiO2/Si wafer. The dry attachment of graphene to the target wafer was processed utilizing a wafer to wafer bonding technique in vacuum. We measured the microscopic image, raman spectra and electrical properties of transferred graphene. Optical and electrical properties of the transferred graphene by bubbles/dry are better than those obtained by mechanical/wet transfer.