Low temperature doping of poly-SiGe films with boron by co-sputtering

SiGe films were boron doped by co-sputtering from Si-Ge-B target. Crystallization of amorphous Sice films and dopant activation were realized by furnace annealing at 550 and 570 degrees C, temperatures which are suitable for processing on Coming glass 7059. The composition of boron doped films and their crystallization process were analyzed by Rutherford backscattering spectroscopy, X-ray photoelectron spectroscopy and X-ray diffraction. Electrical properties of the films were characterized in Van der Pauw structure and by spreading resistance. Boron concentration incorporated in the films was in the range of 2 to 10% and the activated carrier concentration was between 6 x 10(18)-6 x 10(20) cm(-3). Very low resistivity of SiGe boron doped films in the range of 3-5 m Omega cm was obtained. It was also found that increased boron concentration leads to retarded crystallization of SiGe films. (C) 2000 Elsevier Science S.A. All rights reserved.