Published online by Cambridge University Press: 15 February 2011
Dopant patterns of 250-nm linewidth have been written in silicon by localized heating with a cw laser beam, and then transferred into positive and negative surface-relief patterns by preferential etching. The tightly focused beam both generates free dopant atoms and simultaneously promotes solidstate diffusion into the substrate. Because of the nonlinear dependence of diffusion rates on temperature, the linewidths of the patterns are substantially narrower than those of both the temperature and the laser-beam profiles on tile surface. In addition, an enhancement is observed in diffusion rates under the strong thermal gradients associated with highly localized heating.
This work was supported by the Defense Advanced. Research Projects Agency, the, Department of the Air Force, in part under a specific program sponsored by the, Air Force Office of Scientific Research, and by the Army Research Office.