Nano-Particles and Nano-Phase Network Structured FeCo Thin Films using Repetitive Plasma Focus Device

Summary form only given. A repetitive plasma focus device has been successfully used to deposit FeCo thin films using two different methods. Firstly, the conventional central hollow copper anode is fitted with a solid FeCo rod with a 4 mm hole. The hot and dense plasma, produced during collapse phase, ablates the FeCo rod and the ablated material is deposited on silicon substrate placed at 25 cm from anode top. Second method uses energetic electrons produced in focus device. The energetic electrons are extracted through the anode hole in a lower chamber to ablate the FeCo target disc to deposit thin films. In both the methods, different numbers of focus deposition shots were fired at 1 Hz repetition rate and at 12 kV charging voltage with 12 mbar hydrogen. The SEM images of 30 shots deposition, by first method, show that the film surface is covered with 100 nm agglomerates which are composed of smaller grains of the size approximately about 20-30 nm. For 100 shots deposition, a different surface morphology is observed with complex distribution of nano-wire like network on the top of a carpet like background. When the number of the shots is increased further, much denser network structure is observed. The EDX of the samples show that the deposited films are stoichiometric. The XRD patterns show that the as-deposited films are crystalline. The films deposited using energetic electrons (second method) also show the nano-phase morphology but the nano-wire kind of the network is not observed on these films. The average size of particle agglomerate is found to vary from 30 to 100 nm. The size of the particles which form these agglomerates, however, is much smaller, less than 30 nm. The paper thus report the first ever use of repetitive plasma focus device as the energetic electron source for thin film deposition