Approaches towards the synthesis of superior precursors

Synthetic approaches from CVD community have been reviewed by Working Group 2.
The synthetic approaches of participants Heinrich Lang, Anjana Devi, Mats Tilset, Iwona Szymanska, Markku Leskelä, and Sven Barth were presented at the general meetings CELINA 2014 and CELINA 2015 .

During the 1960s and 1970s, a wealth of metal organic precursors has been described in literature but many have been abandoned. A strategy towards precursor developments within CELINA has been to revisit this old chemistry and modify synthetic routes for current precursor needs:

Synthetic routes towards bimetallic precursors

• F. Porrati, M. Pohlit, J. Müller, S. Barth, F. Biegger, C. Gspan, H. Plank, M. Huth:
  Direct writing of CoFe alloy nanostructures by focused electron beam induced deposition from a heteronuclear precursor,
  Nanotechnology 26 (2015) 475701.

Synthetic route to Ru precursor (η³-C₃H₅)Ru(CO)₃Br

• Rachel M. Thorman, Joseph A. Brannaka, Lisa McElwee-White, Oddur Ingolfsson:
  Low energy electron-induced decomposition of (η³-C₃H₅)Ru(CO)₃Br, a potential focused electron beam induced deposition precursor with a heteroleptic ligand set,
  Phys.Chem.Chem.Phys. 19 (2017) 13264-13271.

Synthetic route to different silacyclohexanes

• Ragesh Kumar T P, Sangeetha Hari, Krishna K Damodaran, Oddur Ingólfsson, Cornelis W. Hagen:
  Electron beam induced deposition of silacyclohexane and dichlorosilacyclohexane: the role of dissociative ionization and dissociative electron attachment in the deposition process,
  Beilstein J. Nanotechnol. 8 (2017) 2376–2388.

Systematic variations of precursor architectures based on the known properties and performance in FEBID of specific previously investigated precursors were also proposed:

Design rules for FEBID precursors derived from previous insight on precursor fragmentation

• Julie A. Spencer, Samantha G. Rosenberg, Michael Barclay, Yung-Chien Wu, Lisa McElwee-White, D. Howard Fairbrother:
  Understanding the electron-stimulated surface reactions of organometallic complexes to enable design of precursors for electron beam-induced deposition,
  Appl. Phys. A 117 (2014) 1631.

The synthesis of small volatile Au precursors revisited - effect of ligand architecture

• W. F. van Dorp, X. Wu, J. J. L. Mulders, S. Harder, P. Rudolf, J. T. M. De Hosson,
  Gold Complexes for Focused-Electron-Beam-Induced Deposition
  Langmuir 2014, 30, 12097−12105.

• Ali Marashdeh, Thiadrik Tiesma, Niels J. C. van Velzen, Sjoerd Harder, Remco W. A. Havenith, Jeff T. M. De Hosson, Willem F. van Dorp,
  The rational design of a Au(I) precursor for focused electron beam induced deposition,
  Beilstein J. Nanotechnol. 8 (2017) 2753–2765.

As essential step required for reaching this objective, a number of collaborations with synthetic groups have been established. More conclusions about favourable properties will likely emerge and need to be translated into stable and volatile precursors.