| AVS 55th International Symposium & Exhibition | |
| Thin Film | Monday Sessions |
| Session TF-MoA |
| Session: | ALD: Functionalization and Surface Chemistry |
| Presenter: | W.M.M. Kessels, Eindhoven University of Technology, The Netherlands |
| Authors: | W.M.M. Kessels, Eindhoven University of Technology, The Netherlands H.C.M. Knoops, Eindhoven University of Technology, The Netherlands A.J.M. Mackus, Eindhoven University of Technology, The Netherlands S.A.F. Dielissen, Eindhoven University of Technology, The Netherlands M.C.M. van de Sanden, Eindhoven University of Technology, The Netherlands |
| Correspondent: | Click to Email |
Due to its chemical stability and excellent electrical properties platinum has wide application prospects in catalysis and microelectronics. Recently the deposition of Pt films in complex 3D structures by ALD has gained interest for catalyst applications in fuel cells and as a current collector layer in Si-integrated solid-state thin film Li-ion batteries. In this contribution we report on thermal and remote plasma ALD of Pt films using MeCpPtMe3 precursor combined with O2 gas and O2 plasma, respectively. For the thermal process the results obtained by Aaltonen et al.1 were reproduced (growth per cycle is 0.045±0.005 nm) and special attention was given in characterizing the growth incubation period on Si with thermal and native oxide by using in situ spectroscopic ellipsometry. With the new remote plasma ALD process (growth per cycle is 0.047±0.005 nm) the growth incubation could be reduced to a few cycles yielding the possibility to initialize Pt growth by depositing a remote plasma ALD “seed layer” and thickening the film by thermal ALD. A short plasma exposure (0.5 s) was necessary to deposit Pt films with no detectable amount of oxygen while a long O2 plasma exposure (5 s) resulted in platinum dioxide (PtO2.2, growth per cycle is 0.048±0.004 nm). Pt films were deposited with a mass density of 20.8 g/cm3 and an electrical resistivity of 14 μΩ cm, both close to the bulk values of 21.4 g/cm3 and 10.8 μΩ cm. The platinum oxide films had a mass density of 8.9 g/cm3 and they showed a semi-conductive behavior (resistivity of >100 Ω cm, bandgap 0.85 eV). In addition to ex situ film analysis, several in situ diagnostics have been employed. With spectroscopic ellipsometry the film thickness and (optical) film properties were monitored as a function of the number of cycles. From the Drude parameters in the Drude-Lorentz optical parameterization of the platinum, information about mass density and electrical resistivity was extracted. With infrared transmission spectroscopy the consumption of MeCpPtMe3 precursor was measured while currently also the reaction products generated during the surface reactions are being investigated.
1 T. Aaltonen, M. Ritala, T. Sajavaara, J. Keinonen, and M. Leskela, Chem. Mater. 15, 1924 (2003).