Atomic Layer Deposition of Intermetallic Fe4Zn9 Thin Films from Diethyl Zinc

摘要

We present a new type of atomic layer deposition (ALD) processfor intermetallic thin films, where diethyl zinc (DEZ) serves as a coreactant. In ourproof-of-concept study, FeCl3 is used as the second precursor. The FeCl3 + DEZprocess yields in situ crystalline Fe4Zn9 thin films, where the elemental purity andFe/Zn ratio are confirmed by time-of-flight elastic recoil detection analysis (TOF-ERDA), Rutherford backscattering spectrometry (RBS), atomic absorptionspectroscopy (AAS), and energy-dispersive X-ray spectroscopy (EDX) analyses.The film thickness is precisely controlled by the number of precursor supply cycles,as expected for an ALD process. The reaction mechanism is addressed bycomputational density functional theory (DFT) modeling. We moreover carry outpreliminary tests with CuCl2 and Ni(thd)2 in combination with DEZ to confirm that these processes yield Cu-Zn and Ni-Zn thinfilms with DEZ as well. Thus, we envision an opening of a new ALD approach based on DEZ for intermetallic/metal alloy thin films.