Film Deposition and Structure

The amorphous superlattice materials were fabricated in thin film form by a plasma-assisted chemical-vapor-deposition process in which the composition of the reactive gas in the plasma reactor is changed periodically without interrupting the plasma (Abeles and Tiedje, 1983). A schematic digram of the capacitive plasma reactor used is shown in Fig. 1. The substrates are placed on the anode, and both cathode and anode are heated to 180 - 220°C. In order to achieve sharp interfaces between the layers, the residence time Tr of the gas molecules in the reactor must be short compared with the time Tm 

Deposition system. Valves VA and VB open and close alternately to admit gases A or B C, stainless steel bell jar D, substrate E, heaters F, anode G, cathode H, insulator. 

Transmission electron microscopy (TEM) and x-ray diffraction provide complementary information on the structure of the superlattices. Transmission electron microscopy gives an image of the film cross section and provides information on localized defects the interpretation of the data can be relatively simple, but the sectioning of the samples for microscopy is a difficult technical task. X-ray diffraction provides information on the struc- 

with an rms fluctuation in layer thickness of 5.4 A (Abeles et al, 1984a). 

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M. Ohring, 2002, Materials Science of Thin Films — Deposition and Structure,... 

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