Polycrystalline boron carbide (B4C) thin films have been prepared by a pulsed ion-beam evaporation technique without heating substrates or annealing samples. Here, we clearly demonstrate the possibility of preparing B4C thin films for electronic device applications.

No abstract

Boron carbide (B 4 C) is known as a material having hardness, wear resistance and stability at high temperature. The preparation of thin films of B 4 C, therefore, is very important from the viewpoint of industrial applications. We have experimentally attempted to prepare thin films of B 4 C using the pulsed ion-beam evaporation (IBE) technique, where high-density ablation plasma is produced by an intense pulsed ion beam interaction with the target. The crystallized B 4 C thin films have been successfully deposited on a Si (100) substrate by front-side and mask-side deposition. Absorptions associated with the B-C combination and the vibration of B 12 -B 12 clusters have been observed by Fourier transform infrared spectroscopy. The Vickers hardness of the film deposited by front-side deposition is observed to be HV ∼ 2300.

Boron carbide (B4C) is known as a material having hardness, wear resistance and stability at high temperature. It can be applied, for example, as a coating material for cutting tools. The preparation of thin film of B4C, therefore, is very important from the viewpoint of the industrial applications. We have experimentally attempted to prepare thin film of B4C using the pulsed ion-beam evaporation (IBE) technique, where high-density ablation plasma is produced by an intense pulsed ion beam interaction with the target. Various configurations of IBE have been studied by front-side, back-side and mask-side depositions. The crystallized B4C thin films have been successfully deposited on Si(100) substrate by front-side and mask-side depositions. Absorptions associated with the B-C combination and the vibration of B12-B12 clusters have been observed by Fourier transform infrared spectroscopy. The Vickers hardness of the film deposited by front-side deposition is observed to be HV-2300.

Thin films of boron carbide (B 12+x C 3-x ) were prepared on glass substrates by a pulsed ion-beam evaporation method. A pulsed proton beam with an energy of 1 MV (peak) and a current of 60 kA was focused on sintered B 12+x C 3-x targets. Ablation plasma was formed from the irradiated targets and thin films were prepared on Pyrex and SiO 2 glass substrates at room temperature. From results of X-ray diffraction, the thin films consisted of a B 12+x C 3-x phase. Using a known relationship between the composition and the lattice parameters, the composition of B 12+x C 3-x thin films was estimated to be x = 0.3 and 1.0, which were close to the nominal composition of the targets. These results indicate that B 12+x C 3-x with different carbon contents has been successfully prepared by IBE without substrate heating or sample annealing. Thermoelectric properties of the thin films were measured. A B 12+x C 3-x thin film with estimated composition of x =0.9 exhibited the highest power factor at room temperature among the B 12+x C 3-x samples reported.