Studies of metallic thin film growth in an atomic layer epitaxy reactor using M acac/ MsNi, Cu, Pt/precursors

Feasibility of metallic thin film growth by atomic layer epitaxy ALE.was studied in the case of divalent metal b-diketonate-type precursor M acac.2 MsNi, Cu and Pt.at 2508C and 1 mbar. Metallic films were obtained by two different approaches: i. direct layer-by-layer reduction of the adsorbed precursor by H2, and ii. by first depositing a metal oxide thin film by ALE and then converting it to the metallic form by a separate reduction step. The latter case was demonstrated by converting a NiO thin film, deposited at 2508C on glass substrate with O3 as an oxygen source, to metallic Ni at 2608C and 1 atm by 5% H2. AFM study indicated, however, pinhole formation and, thus, deformation of the initial dense structure of NiO. In the case of direct layer-by-layer reduction by H2, attention was focused on the effects of the substrate on the film growth by applying Ti, Al, Si 100.and glass substrates. X-ray photoelectron spectroscopy XPS.and X-ray diffraction XRD.studies indicated that metallic Ni, Cu and Pt film growth proceeded preferably on Ti and Al substrates. On Si substrate, the film growth was restricted by interdiffusion and silicide formation; whereas on the glass substrate, the film growth was related to the gas phase stability of the precursors and proceeded mainly by pyrolysis. q2000 Elsevier Science B.V. All rights reserved