Single crystal Ge films (∼10 μm) have been epitaxially grown on polished (100) NaCl substrates at 450 °C by plasma enhanced chemical vapor deposition (PECVD). Upon cooling, the films were separated from the substrate by differential shear stress which left handleable free-standing films of Ge. Growths were achieved by nucleating at minimum plasma power (∼10 W) for very short intervals and then raising the power to 65 W to increase the growth rate to approximately 10 μm/h. Substrate exposure to the plasma at too high a power for too long a time was found to sputter and erode the surface, thus substantially degrading the nucleation process and the ultimate growths. The free-standing films were visually specular and exhibited a high degree of crystalline order when examined by x-ray diffraction. Auger electron spectroscopy (AES) and energy dispersive analysis of x rays (EDAX) showed no detectable bulk contamination. The films were found to be p type with a carrier concentration of approximately 3×1016 cm−3, a resistivity of 0.11 Ω cm, and a Hall hole mobility of 1820 cm2 V−1 s−1 at room temperature.

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This report describes the o p t i m i z a t i o n of the firing process used in the production o f Y B a 2 C~3 0 7 -~ thick films screen printed on y t t r i astabilized zirconia substrates. The highest c r i t i c a l current density (Jc) values were obtained b y employing a double layer printing technique i n which a single superconductive layer was printed onto a zirconia substrate and fired, followed by t h e subsequent deposition and firing of a s e c o n d superconductive layer. Using this procedure, t h i c k film superconductors with a superconductive transition temperature (T,) of 85K and a Jc of 1 3 0 A/cm2 were obtained by sintering the printed f i l m s at 950°C for 90 minutes, followed by a six hour oxygen annealing treatment at 600°C. S p e c i m e n s sintered for comparable periods of time at 940 and 960°C did not exhibit superconductive b e h a v i o r above 77K due to either incomplete microstructural development or thermal decomposition of t h e superconductive phase respectively.

Comparative study of plasmaenhanced chemical vapor deposited silicon nitride films

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