A simple analytical approach, based on an energy balance equation, is introduced to describe the melt region of a semiconductor under a focused pulsed laser irradiation. In this model, an approximate analytical solution of the time-dependent hemispherical melt radius is calculated, and satisfactorily compared with experiments on silicon irradiated with a focused, 1 mus beam diameter, visible laser of a few watts with pulse widths of 0.03-10 mus. (C) 2002 Elsevier Science B.V. All rights reserved.