Direct sub-mu m lateral patterning of SOI by focused laser beam induced oxidation

We have developed a method for resistless patterning of Silicon-On-insulato r (SOI) in order to directly achieve lateral dielectric isolation. Our meth od employs a diffraction limited laser spot of a cw argon laser which is sc anned across the SOI:surface and directly oxidizes the silicon in ambient a tmosphere. We investigate the dependence of the line width on the laser pow er and laser wavelength and scanning speed by AFM measurements. Line widths as narrow as 200 nm are achieved. We have fabricated in-plane-gate transis tors with effective channel widths of 250 nm and excellent gate to source-d rain isolation. We further demonstrate how our method can be extended for l ocal simultaneous oxidation and doping of the silicon surface with high spa tial resolution. A novel in-plane-FET da ice has thus been realized.