Nanoscale opening fabrication on Si (111) surface from SiO₂ barrier for vertical growth of III-V nanowire arrays

We reported here a selectively additive process to fabricate nanoscale openings of an Si (111) surface from an SiO₂ barrier layer. Such nanoscale openings are made for the growth of vertical III–V nanowires. The Si (111) surface protected by a patterned SiN_x layer was thermally oxidized, which resulted in a selectively added SiO₂ barrier layer. After removing the SiN_x, nanoscale openings of the Si (111) surface were exposed for the nanowire growth. Arrays with patterned nanoholes of varied diameters from 60 nm to 334 nm have been used for position-controlled catalyst-free growth of vertical InAs nanowire arrays by metal-organic chemical vapor deposition. Correlations between the nanohole diameter and the diameter, length and growth yield of as-fabricated nanowire arrays have been investigated, showing a repeatable stability. This technique offers an alternative approach for the fabrication of novel III–V nanowire devices using vertical array configuration. A lateral thermal oxidation effect led to a smaller size of the Si opening than that of the SiN_x protection nanoislands; therefore, the technique also offers a controllable way to produce nanoholes with an ultra-small diameter. (paper)