Pulsed ion-beam melting of silicon

Pulsed ion beams have been used to melt and regrow single-crystal silicon. By using the technique of transient conductivity, the effects of ion species and pulse duration have been determined. For heavier ions, with shorter pulses (70 ns), melt is initiated at lower energy densities. The regrowth velocity is also greater. For lighter ions (${\mathrm{H}}^{+}$) with longer pulses (140 ns), computer simulations show that the temperature gradient is uniform over the top 1.5 μm of silicon. Melt depths of up to 1.7 μm, and regrowth velocities as low as 1.2 m/s, are obtainable. For both types of pulses, the ion energies were distributed between 0 and 400 keV. The total energy density was varied between 0.76 and 2.0 J/${\mathrm{cm}}^2$.