Low-energy electron interaction and focused electron beam-induced deposition of molybdenum hexacarbonyl (Mo(CO)6).

Po-Yuan Shih,Maicol Cipriani,Christian Felix Hermanns,Armin Gölzhäuser,Klaus Edinger,Jens Oster,Oddur Ingólfsson

doi:10.3762/bjnano.13.13

Abstract

Motivated by the potential role of molybdenum in semiconductor materials, we present a combined theoretical and experimental gas-phase study on dissociative electron attachment (DEA) and dissociative ionization (DI) of Mo(CO)6 in comparison to focused electron beam-induced deposition (FEBID) of this precursor. The DEA and DI experiments are compared to previous work, differences are addressed, and the nature of the underlying resonances leading to the observed DEA processes are discussed in relation to an earlier electron transmission study. Relative contributions of individual ionic species obtained through DEA and DI of Mo(CO)6 and the average CO loss per incident are calculated and compared to the composition of the FEBID deposits produced. These are also compared to gas phase, surface science and deposition studies on W(CO)6 and we hypothesize that reductive ligand loss through electron attachment may promote metal–metal bond formation in the deposition process, leading to further ligand loss and the high metal content observed in FEBID for both these compounds.

Highlights

Studies on Mo-based semiconductor materials for the application as thin films with wafer-scale thickness homogeneity [1] and for solar hydrogen production [2] have attracted interest in the last years
We have reported on the interactions of low-energy electrons with the focused electron beam-induced deposition (FEBID) precursor Mo(CO)6 and on the composition of deposits made with this precursor
The dominant dissociative electron attachment (DEA) channel is the formation of the anionic fragment [Mo(CO)5]− through a low-energy contribution close to 0 eV electron energy and further CO loss is observed through distinct contributions at higher energies

Summary

Introduction

Studies on Mo-based semiconductor materials for the application as thin films with wafer-scale thickness homogeneity [1] and for solar hydrogen production [2] have attracted interest in the last years. For applications of such types a good and targetoriented fabrication control of molybdenum nanostructures is important. This may be achievable by focused electron beam-induced deposition (FEBID). The organometallic precursors are continuously supplied to a substrate surface in proximity to the impact side of a tightly focused, high-energy electron beam in a high-vacuum instrument. The organometallic precursor is completely dissociated through the interaction with the high-energy electrons, leaving a pure metal deposit on the sur-

Methods

Results

Conclusion