Quantitative ion beam process for the deposition of compound thin films

Abstract

We describe a quantitative ion beam technique for the deposition of compound thin films. The metal atom flux is supplied by inert ion beam sputtering, and the reactive flux is supplied by a low-energy ion beam directed at the growing film, allowing the fundamental deposition parameters of arrival rates, ion energy, and direction to be measured and controlled. Analysis gives the sputtering yields and incorporation probabilities as a function of film composition, arrival rate ratios, and ion energy. Results are presented for Al films deposited under a range of N2+ ion bombardment (100–500 eV) up to arrival rate ratios exceeding the value needed to form AlN. Nitrogen ions are almost fully incorporated into Al films, and excess N is rejected above the composition N/Al=1. The microstructure is shown to depend on the N/Al arrival rate ratio and the nitrogen ion energy used during deposition.

Effects of ion energy and arrival rate on the composition of zirconium oxide films prepared by ion-beam assisted deposition

“…from AlN films grown by dual ion beam deposition method. 17 They reported incorporation probabilities and sputtering yields of the individual film atoms as a function of the ARR͑N/Al͒ and observed a preferential sputtering of Al at ARR͑N/Al͒ less than a stoichiometric AlN. The present results can be interpreted qualitatively by their experimental results, provided that the behavior of Zr toward the O ions is similar to that of Al toward the N ions.…”

Statistical analysis of the effect of deposition parameters on the preferred orientation of sputtered AlN thin films

“…Lower deposition rate, and higher directionality and energy of the depositing flux, are favorable conditions for the (002) preferred orientation. Bombardment of the growing film is also favorable for particle energies below 200 eV [19]. Particles energy values below 200 eV is a reasonable assumption for particles moving across the plasma sheath accelerated by an electric field proportional to the difference between the plasma potential and the floating substrate bias.…”

Effect of intrinsic stress on preferred orientation in AlN thin films

“…In the majority of cases the crystallites of AlN thin films are found to have a preferred crystallographic orientation with respect to the plane of the substrate. [12][13][14][15][16][17][18][19] In most cases, [13][14][15][16] the preferred orientation reported is with the c axis perpendicular to the plane of the film. Windischmann, 13 used a nitrogen ion bombardment energy of 100 eV and reported intrinsic stresses of up to 2.8 GPa in AlN films with the c axis perpendicular to the film.…”

“…Windischmann, 13 used a nitrogen ion bombardment energy of 100 eV and reported intrinsic stresses of up to 2.8 GPa in AlN films with the c axis perpendicular to the film. For growth using energies above 100 eV, [17][18][19] a change to a c axis in the plane of the film orientation was reported for energies between 300 and 500 eV.…”