CRYSTALLIZATION OF A-SI-H FILMS BY RAPID THERMAL ANNEALING

The effect of rapid thermal annealing on the structural properties of hydrogenated amorphous silicon (a-Si:H) as a function of annealing tim e and temperature is studied by spectroscopic ellipsometry in the spec tral region of 300-1200 nm, X-ray diffraction (XRD) and reflection hig h-energy electron diffraction (RHEED) methods. After annealing at 850 and 1050 degrees C, the a-Si:H films are predominantly amorphous and c onsist of two sublayers which contain a mixture of amorphous and cryst alline silicon and voids, the volume fractions of which are temperatur e-dependent. Annealing of these a-Si:H samples at 1250 degrees C resul ts in a completely crystallized and void-free structure. (C) 1998 Else vier Science B.V. All rights reserved.