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Oxygen indiffusion during pulsed laser annealing of silicon has been studied 16 16 using the 8 0(m,m) 8 0 resonance at 3.045 MeV. Anneals were carried out with a Q-switched ruby laser, energy density of the pulses 1.5 J/cm 2 , pulse width 20 ns. No evidence for oxygen indiffusion was found, neither for ion-implanted single pulse air-annealed silicon nor for a silicon wafer, cleaned with 8 laser shots in a UHV environment. In the latter case, the upper limit of the oxygen concentration was found to be 3.1* 1018 at/cm 3 , which is lower than the solid solubility limit of oxygen in silicon. The non-occurrence of indiffusion is consistent with the dissolution time of Si0 2 in Si, which is orders of magnitude longer than the melt duration of the Si-substrate.

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ABSTRACT300 keV Kr ion irradiations with doses varying from 2× 1015 to 2× 1016 at/cm2 have been applied to initiate mixing of Cu-Au and Cu-W systems. As under normal thermodynamic conditions the Cu-Au system is miscible whereas the Cu-W system is not, the comparison of both systems provides a test for the current theories on ion-beam mixing. A pronounced difference in mixing phenomena is observed for both systems; in the Cu-Au system atomic displacements are one order of magnitude larger than those in the Cu-W system. In addition, a drastic temperature dependence of ion-beam mixing in the Cu-Au system has been found. The mixing is suppressed by lowering the substrate temperature during irradiation. These results show that radiation enhanced diffusion is the mechanism underlying the ion-beam mixing of Cu and Au. Results for the Cu-W system are consistent with a collisional mixing model.