DESORPTION AND OTHER EFFECTS OF PULSED-LASER ANNEALING OF HYDROGEN-IMPLANTED SILICON

The behavior of H-ion-implanted c-Si was investigated at temperatures up to the melting point, on the 10(-8) s time scale, using pulsed-laser annealing in conjunction with quantitative analysis of the released gas. Laser reflectivity, scanning electron microscopy, and surface profilometry were also used to characterize implantation and annealing effects. Computational kinetic modeling of H release as a function of laser energy is applied to the interpretation of the data. The desorption of H implanted at 1 or 2 keV takes place at > 1000 K, without extensive surface deformation, and can be fitted by detrapping with an activation energy (almost-equal-to 2 eV) that slowly decreases with the H/Si ratio in the range 4%-27%; contrary to expectation, no limitation by diffusion is observed. Implanted at 5 or 10 keV and H/Si greater-than-or-equal-to 20%, H is released at > 550 K by blister rupture. In spite of the differences between the results for low and high implantation energies, a unified picture emerges, involving a layer with a high-temperature H mobility greater than that of ordinary atomic diffusion.