LiU researcher, Professor Henrik Pedersen and his Pedersen group have demonstrated a cleaner way to deposit iron films at low temperatures using a pulsed form of electron driven chemical vapor deposition. Traditional CVD struggles with iron because reducing the precursor usually requires high heat or reactive gases. Electron CVD avoids this by using plasma electrons to break down the precursor directly on the surface, but common iron precursors like ferrocene often leave heavy carbon contamination.
The new study shows that switching from continuous operation to timed pulses sharply improves purity. By separating the precursor dose and the plasma step, the process limits unwanted gas phase reactions and gives carbon rich fragments time to be removed. The researchers report that carbon levels drop from about 32 percent in continuous e CVD to about 10 percent in the pulsed process. Using a turbomolecular pump during the purge step improves this even further.
“These results shows that we are starting to be able to control this new form of CVD, it also hints on which types of precursor molecules that we should use”, says Henrik Pedersen.
The team also tested an amidinate based iron precursor, which showed more predictable surface behavior but produced similar impurity levels and slower growth.
“We are working on similar processes for more metals with very exciting results”, says Henrik Pedersen.
The results show that pulsed electron driven CVD can produce cleaner iron films at low temperatures, an important step for electronics and magnetic applications where heat sensitive materials are involved.
Find the publication here.
