Thin films (0.3–5 μm) of an amorphous fluoropolymer (AF) derived from the copolymeric material Teflon AF 1600 were deposited on Si (100) wafers by vacuum pyrolysis. Infrared spectroscopy indicated that the composition of the deposited films was similar to the source material. The deposited films were amorphous by x-ray diffraction. The surface morphology contained micropores which did not extend through films deposited at a low rate. The refractive index was ∼1.2 at 633 nm. Comparisons are made to films derived from ordinary Teflon (also by pyrolysis). The mechanism for the repolymerization of the Teflon AF copolymer at the substrate surface is discussed.

Diffusion of Ag from epitaxial layers into Si(111) is studied under an anneal of 450–500 °C using the secondary ion mass spectrometry depth profiling tool. The measurements yielded values of the diffusion constant (0.80–1.6 × 10−15 cm2/s) which fall short of literature values extrapolated from higher-temperature Arrhenius laws. Diffusion of Ag into SiO2 was also measured directly. The observed diffusivity of 1.0 × 10−15 cm2/s is a factor of ∼ 105 smaller than expected from previous determinations of the diffusivity of Ag+ in SiO2 obtained from anneals in forming gas. The discrepancy may be due to changes in the local electrostatic environment in the absence of acceptor levels in SiO2 from dissolved gases which are absent in vacuum.

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Carbon segregation to the lowindex surfaces of an Fe-10 at.% Si single crystal The room temperature growth of 1000-1500 b; Ag films on HF-dipped Si substrates is studied as a function of self-ion (Ag+ ) energy during deposition. In all cases the tilms contained a mixture of epitaxial grains and randomly oriented ( 111) grains. The orientations observed were Ag(lll)/Si(lll) with both type A (Ag(llO)//Si(llO)) and type B (Ag(llO)//Si(ll4)) twins; Ag( 1 lO)/Si( 110) with Ag(OOl)//Si(OOl);and Ag( lOO)/Si( 100) with Ag(O1 l)// Si(Ol1). All three constructions match three Si atomic rows with four Ag rows. As judged by the ratio of epitaxial to nonepitaxial grains, the strength of the epitaxy was seen to decrease in the order ( 111) > (110) > (100). Increasing the Ag+ ion energy during the deposition was generally seen to decrease this ratio. Annealing of the Ag/Si( 100) fihns induced preferential ( 100) grain. growth.' 466

The observation of room-temperature epitaxy of vapor-deposited thin Ag films on Si(111) accomplished under conventional vacuum conditions is reported. Epitaxy was also observed at 350 °C. The films were deposited using a partially ionized beam deposition system, and were typically 1500 Å thick. Epitaxy was confirmed via pole-figure analysis. Scanning electron microscopy revealed excellent surface flatness even for the room-temperature films. Contrary to previous observations, the growth was found to proceed by the layer mode, even at the elevated temperature. This change in morphology is attributed to the enhanced density of nucleation sites due to the energetic ions.