Comparison of Pd electron beam induced deposition using two precursors and an oxygen purification strategy.

Focused electron beam induced deposition (FEBID) allows the creation of nanoscale structures through dissociation of an organo-metallic precursor by electrons at the beam impact point. The deposition of Pd can be interesting for its catalytic behavior and ability to contact carbon based materials. Two precursors were investigated-Pd(hfac)(2) and (Cp)Pd(allyl)-and two deposition methods: with and without an in situ oxygen purification process. The deposition parameters can be tuned for the Pd(hfac)(2) precursor to provide a deposition with 23 +/- 2 at.% of Pd and a main component of C at 51 +/- 3 at.% and minor components of O and F. An in situ purification process using O-2 was much faster than expected and improved the Pd content to up to >65 at.% while reducing the C to similar to 20 at.%, and avoiding the oxidation of Pd. The resistivity was similar to 100 mu Ohm . cm and compares favorably with a bulk value of 10 mu Ohm . cm. The (Cp) Pd(allyl) precursor is interesting because it does not release fluorine during the deposition and hence it does not etch a possible substrate. Its FEBID deposition had a composition of 26 +/- 5 at.% of Pd with 74 +/- 5 at.% of C. The O-2 purification process can improve the Pd content up to similar to 60 at.% while reducing C to <20 at.%, but also increasing the O content to 18 at%, which was released afterwards. The best resistivity was measured at similar to 1000 mu Ohm . cm, although better values can be anticipated for longer post treatment times.