Solubility limit of impurities in silicon after laser induced melting

The solubility of several dopants (Sb, Ga, Bi, In) in laser treated silicon has been investigated. The dopants were introduced by vacuum deposition followed by ruby laser irradiation. Their solubility was determined by Rutherford backscattering spectroscopy measurements in channelling and random conditions. In all cases, a maximum solubilityC _S ^* , much higher than the equilibrium solubility limitC _S ⁰ and independent of the pulsed laser energy density, was found. The values obtained are in good agreement with those calculated from a simple model based on phase diagram considerations, using the relationship: $$C_S^* = \frac{{C_S^0 }}{{k_0 }}k^* ,$$ wherek ₀ andk ^* are the equilibrium and effective distribution coefficients. Finally, the existence of a new solubility limit for a laser treatment is discussed.