Germanium n+/p junction formation by laser thermal process

Abstract

In this letter, an n+ p junction on a germanium substrate, formed by phosphorous implantation and subsequent laser thermal annealing process, is demonstrated. The effects of laser energy fluence and irradiation pulse number on the redistribution of dopant atoms have been investigated. The secondary-ion-mass-spectrometry results indicate that steplike dopant profiles are formed with dopant atoms extending deeper upon increased laser energy fluence and successive pulse number. After being irradiated at a laser energy fluence of 0.16 J cm2 with two successive pulses, the junction exhibits a sheet resistance of ∼50 Ohmsq for n+ region, a comparable current-voltage characteristic, and much less phosphorus dopant diffusion in comparison with those formed by rapid thermal process annealing. © 2005 American Institute of Physics.