Crystallization of hydrogenated amorphous silicon deposited at high rate by dc magnetron sputtering

The crystallization of hydrogenated amorphous silicon (a-Si:H) films is studied by thermally annealing in the temperature range between 620 and 660 degrees C. The films are deposited by de magnetron sputtering on a quartz substrate at a rate around 1.5 nm/s. The crystallization kinetics are studied from the electrical conductivity which is measured in-situ under vacuum during thermal annealing. In the growth regime, the electrical conductivity variation can be fitted by a known crystallization model. This model permits determination of the characteristic time (t(c)) of the kinetics. The variation of t(c) versus the temperature of annealing shows a linear dependence in the Arrhenius representation. The t(c) and its activation energy are related to the growth and nucleation phenomena and t(c) is dependent on the film thickness. Its activation energy is 3.4 eV for a 0.64-mu m thick film and 2.4 eV for a 1.4-mu m thick film. (C) 1998 Elsevier Science B.V. All rights reserved.