Conditions for fabrication of highly conductive wires by electron-beam-induced deposition

Conductive wires were fabricated by electron-beam-induced deposition (EBID) using WF6 gas. It was difficult to fabricate highly conductive wires with good reproducibility unless samples were cleaned before EBID. Contamination appears to reduce the conductivity of the wires. O-2 plasma cleaning of samples before EBID seems to reduce contamination growth; however, it is not effective for regions in the vicinity of Au patterns. We found that by combining annealing at 300 degreesC and O-2 plasma cleaning, highly conductive wires could be fabricated with relatively good reproducibility in such regions. A linear relation was found between wire conductance and linedose at lindoses of more than 70 muC/cm. The change in deposition yield estimated from the conductance was about 12% when the gas flux was halved. Wires with a length of less than 40 nm were less conductive than longer wires because of a shortage in gas supply.