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Graphene is a promising material to replace Cu-interconnect metallization under a width of 10 nm. We report a method for evaluating the graphene interconnect wiring structure by conductive atomic force microscopy (C-AFM), which enables the direct measurement of the two-dimensional (2D) resistance distribution and the coverage evaluation of multilayer graphene (MLG) grown on Ni interconnects using a 300 mm damascene process. The resistivity of exfoliated two-layer graphene was measured and a reasonable value of 30 µΩ·cm was obtained. We also measured the resistance of the MLG/Ni stack of 350 nm L/S patterns and confirmed the conduction paths of the MLG/Ni stack. It is demonstrated that the coverage of MLG on Ni interconnects can be estimated more precisely by C-AFM than by backscattered electron scanning electron microscopy (BSE-SEM) observation. C-AFM is demonstrated to be a potential technique for the local conductance evaluation of next-generation interconnects. [ABSTRACT FROM AUTHOR]

Multilayer graphene (MLG) is expected to be a low-resistance and high-reliability interconnect material replacing copper (Cu) in nanoscale interconnects. To achieve low-resistance interconnect with MLG, carrier doping is necessary since the carrier concentrations in pristine MLGs are low. In this work, the effects of bromine (Br) doping by intercalation on the carrier concentration and sheet resistance of exfoliated highly oriented pyrolytic graphite (HOPG) were investigated by measuring the Fermi level shift using ultraviolet photoelectron spectroscopy (UPS) and the four-terminal method, respectively. The Fermi level was shifted downward up to 0.63 eV, and the sheet resistance was reduced to less than 10% of that of the pristine HOPG by increasing the Br concentration. A similar Fermi level shift was observed for the commercially available CVD-MLG. Br doping is thus promising for low-resistance MLG interconnects from the perspective of carrier doping. [ABSTRACT FROM AUTHOR]

Total photoyield spectroscopy (TPYS) measurement is applied to boron (B)-doped polycrystalline diamond, which shows an extremely low cathode fall voltage (Vc) in glow discharge operation. The B-doped diamond film grown on a molybdenum (Mo) substrate shows Vc of about 43 V after hydrogenation with a small amount of hydrogen added to argon (Ar + 0.03% H2). This Vc value is almost 1/3 that of the Mo substrate without diamond. The TPY spectrum of the diamond after hydrogenation in microwave hydrogen plasma shows obvious onset at 4.5 eV, which is below the band-gap energy of diamond (5.47 eV). This is attributed to the negative electron affinity (NEA), which results in an electron affinity of −1.0 eV. Vc and TPY spectra are also measured for acid treatment condition and Mo. From these experiments, the low Vc values of B-doped polycrystalline diamond depending on the surface treatment correlate to the difference between electron affinities derived from the TPYS measurements. [ABSTRACT FROM AUTHOR]