Electrical Properties of Platinum Interconnects Deposited by
Electron Beam Induced Deposition of the Carbon-Free
Precursor, Pt(PF3)4
Colm O’Regan1,2, Angelica Lee1,2, Piet Trompenaars3, Hans Mulders3, Justin D. Holmes1,2 and
Nikolay Petkov1
1
Electron Microscopy and Analysis Facility, Materials Chemistry and Analysis Group, Tyndall National
Institute and the Department of Chemistry, University College Cork, Ireland.
2
Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity
College Dublin, Dublin 2, Ireland.
3
Electron Optics, FEI, Achtseweg Noord 5 5651 GG Eindhoven, the Netherlands.
Corresponding author:
Email: nikolay.petkov@tyndall.ie
Supporting Information
Figure S1. 2- and 4-point I-V measurements of a liquid Pt precursor which suggest negligible
contact resistance due to identical slopes.
Figure S2. Cross-sectional TEM image of a carbon-free interconnect before annealing outlining
the nominal area (in white) of the interconnect set to 4000 nm2 and the actual cross-sectional area
of the interconnect (in red) that is estimated to be 6000 nm2. The latter is used to calculate the
“true” resistivity of the material instead of the widely used nominal cross-sectional area.
Figure S3. I-V measurements of Pt interconnects before and after annealing in forming gas
(H2/Ar). Right (red) Y axis corresponds to current values after annealing. Top and bottom insets
in both show Pt wire before and after annealing respectively. Scale bar for insets is 3m. (a) I-V
curve for standard Pt interconnect before and after annealing under H2/Ar for two minutes. (b) IV curve for liquid Pt interconnect before and after annealing under H2/Ar for two minutes.
Figure S4. SEM micrographs of (a) standard platinum interconnect and (b) liquid Pt interconnect
after annealing in nitrogen gas for 1 minute.
Figure S5. SEM micrograph of a liquid Pt interconnect deposited on Au/Ni contact pads for
EDX analysis. Points 1 and 2 represent the locations of the EDX scans which were taken on both
the carbon-free and standard Pt interconnects. Point 1 represents the interconnect while point two
is the underlying substrate. The EDX data is given in Table 1 and 2 below.
Table 1. C/Si atomic ratios before annealing for corresponding Pt interconnect devices and the
nearby substrate. The measurements are done on the same chip.
Table 2. C/Si atomic ratios after N2 annealing for corresponding Pt interconnect devices and the
nearby substrate. The measurements are done on the same chip.
Figure S6 (a). SEM micrograph of a carbon-free interconnect deposited on Au/Ni electrodes
after additional annealing at 120 oC for 60 minutes under atmospheric conditions. Inset shows the
area highlighted in the red box and illustrates the formation of phosphorous clusters (shown by
white arrows) along the length of the interconnect.
Figure S6 (b). EDX spectrum of the cluster highlighted by the red arrow in (a). The analysis
confirms the presence of phosphorous in the clusters. The nickel peaks are from the sample
holder in the SEM.