Nanophase copper thin films deposited from a beam source

Abstract

Although thin films formed from beams of nanoparticles or clusters have been discussed since the early 1970s, the question of the usefulness of this method has remained open as few films of any significant thickness have been formed to date. Early attempts did not condense, could only condense a few ''high vapor pressure'' solids, or were so low rate as to make growth too slow to be of use. A new deposition system has been designed and built here at Florida International University along the lines of those of Averback and Haberland, and they appear to have the most promise. The new system was specifically designed for high rate with a high throughput intermediate pressure pump and 2 kW capable dc sputter source. Optically transparent films have been deposited from a copper source but are not yet fully understood. Films were deposited onto single crystal silicon substrates and show a small beam divergence of less than 1°total. The beam is highly nonuniform with maximum intensity on axis, which drops rapidly to zero within less than 10 mm off axis. Deposits have been made using a 1 Torr argonϩhelium sputtering and condensation atmosphere followed by nozzle aperture extraction. Films are affected by the amount of He and by cooling of the sputter chamber walls.

Extended-area deposition of homogeneously sized nanoparticles using modified inert gas condensation technique

“…Various vapor phase techniques are known for synthesis and deposition of NPs [4], including Inert Gas Condensation (IGC). In IGC, NPs are generated from a solid source [5][6][7][8][9][10][11][12]. The atoms, ions and molecules generated from this solid source condense by collision with an inert gas to form NPs.…”

Nanophase films deposited from a high-rate, nanoparticle beam

“…14 It uses sputtering into cooled, flowing gas in a chamber, which contains an exit aperture leading to a differentially pumped deposition chamber. 15 The objectives of the work presented here are to deposit nanophase films from a series of different source metals to make a broad investigation of whether nanoparticles could be formed, and if so, what conditions are required for producing beams for each element. The structure and composition of the films were to be evaluated using a number of analytical methods.…”

“…Figure 1 shows a schematic diagram outlining the main features of the differentially pumped deposition system which is fully described elsewhere. 15 There are three vacuum chambers which communicate by low conductance connections and are maintained at three successively lower pressures by differential pumping. From the right-to the lefthand side in Fig.…”