Structure and Properties of Vacuum-Deposited Cadmium Thin Films

Abstract

Thin films of Cd were prepared by vacuum deposition onto glass plates at temperature of 45 °C and pressure of about 10~6 torr. Several good quality films of various thicknesses (15,000 ~ 28,000 Ä) were made. The films were characterized by strong preferred orientation along the 002 planes parallel to the surface of the substrate, which were found to be thickness dependent. In particular, the 002, 100 and 004 peaks were many times stronger than their corresponding diffraction peaks obtained from powder specimens. Both the real and imaginary parts of the Fourier coefficients were considered for line broadening analysis. The particle size (which is also called the average size of the coherently diffracting domains in a direction perpendicular to the diffracting planes), microstrain (which is usually called the mean strain in a given direction) and faulting were determined. A systematic study for all the diffraction peaks indicates an increase of average particle size J) from 546 to 620 A in the above thickness range with no apparent anisotropy for the 100, 002 and 004 directions. The microstrain, however, decreased as much as 50% in this thickness range and showed a considerable amount of anisotropy. The fault parameters a (deformation fault probability) and ß (growth fault probability) decreased rather rapidly for all directions.