| 초록 |
Abstract: Currently, for large-area graphene electronics, graphene grown on Cu foils by chemical vapor deposition requires transfer to the substrate and lithographic patterning. For that reason, the polymer layer, such as that of poly(methyl methacrylate) (PMMA), must be removed after the graphene transfer to the substrate and lithographic patterning. However, a very thin polymer residue remains on the graphene surface after the polymer layer removal, and this residue can cause many problems, such as decreased electron mobility and the prevention of uniform coverage of high-k dielectrics or metals on graphene during atomic layer deposition (ALD) through prevention of precursor absorption on the graphene surface. In this study, we used a controllable low energy Ar+ ion beam (9.5 eV), we removed the PMMA residue on the graphene surface without damaging the graphene surface. We compared the qualities of HfO2 grown on the graphene surface before and after the Ar+ ion cleaning by fabricating capacitors using HfO2 grown on the graphene surface. The capacitor fabricated using a 20-nm thick HfO2 layer grown on the transferred graphene showed significant leakage current, owing to the non-uniform growth of the HfO2 on the transferred graphene surface. In contrast, the capacitor fabricated using graphene cleaned with the 9.5 eV Ar+ ion beam showed a very low leakage current of less than 10-11 A/cm2, owing to the dense HfO2 thin film grown on the graphene surface. |
