New dithiooxamide derivatives as promising precursors for ALD/MLD applications

Hybrid materials synthesized combining atomic layer deposition and molecular layer deposition (ALD/MLD) results in advantageous material properties owing to the functionalities contributed from the inorganic and organic constituents in the film. The number of MLD precursors that are volatile and compatible with ALD precursors are limited. This study explores the synthesis and characterization of new dithiooxamide (DTOA) derivatives with varied side chain lengths for their application in ALD/MLD processes for the fabrication of Cu-R DTOA thin films. Utilizing bis(dimethylamino-2-propoxy)-copper(II) (Cu(dmap)₂) as the metal precursor, the impact of side chain modifications on the thermal stability and volatility of DTOA derivatives was investigated. Employing complementary analytical tools namely NMR, FTIR and TGA/DSC, the study unveils the structural and thermal properties of synthesized derivatives. From the proof-of-concept ALD/MLD experiments performed, the <i>in situ</i> spectroscopic ellipsometry monitored deposition process demonstrates a controlled linear thickness increase with deposition cycles, affirming the suitability of the DTOA derivatives as MLD precursors. This study delineates the influence of alkyl side chain variation on precursor properties, offering insights into the tailored design of precursors for advanced material deposition.