Atomic layer deposition enabled interconnect technology for vertical nanowire arrays

We have demonstrated an atomic layer deposition (ALD) enabled interconnect technology for vertical, c-axis oriented gallium nitride (GaN) nanowire (NW, 5–10 μm in length, 80–200 nm in diameter) arrays encapsulated by benzocyclobutene (BCB). The nano-scaled ALD multilayer is essential to provide conformal co-axial dielectric (ALD-alumina)/conductor (ALD-tungsten) coverage and precise thickness control for nanowire metallization. Furthermore, we have successfully developed a fabrication process to locally remove and connect tungsten (W) interconnect on NWs. Cross-sectional image taken in a focused ion beam (FIB) tool confirms the conformality of ALD interconnects. Photoluminescence (PL) wavelengths of the nanowires array can be tuned dynamically by changing the input current supplied to ALD-tungsten interconnect which heats nanowires. Such an experiment also demonstrated the quality of interconnect. This interconnect technology can be applied to various vertical nanowire-based devices, such as nanowire light emitting diodes, nanowire-based field effect transistors, resonators, batteries or biomedical applications.