Femtosecond laser direct writing of silicon nanowires

Direct writing using a femtosecond laser provides an accurate, repeatable and efficient means of creating nanoscale lines for electronic applications circumventing the standard fabrication methods that require expensive masks and numerous processing steps. Femtosecond laser writing makes these nanoscale lines by using a phase zone plate to focus the laser pulse onto a silicon substrate in a chemical vapor deposition chamber flowing silane. The silane is decomposed onto the narrow heated area of the substrate as the laser scans across leaving behind a thin line of silicon deposition. This technique utilizes a high precision optical metrology system and a high precision motion control system to make this nano-manufacturing possible. It has been shown to successfully make as many as 100 silicon lines on the order of a few hundred nanometers in width. The size and crystal structure of these lines are characterized using Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM).