Phosphorus atoms implanted in laser crystallized polycrystalline silicon films were activated by a heat treatment in air at 260 degrees C for 1, 3 and 24 h. Analysis of ultraviolet reflectivity of phosphorus-doped silicon films implanted by ion doping method at 4 keV revealed that the thickness of the top disordered layer formed by ion bombardment was 6 nm. It is reduced to 4 nm by a 3 h heat treatment at 260 degrees C by recrystallization of disordered region. The electrical conductance of silicon films implanted increased to 1.7 x 10(5) S/sq after 3 h heat treatment. (C) 2005 Elsevier B.V. All rights reserved.