Stability Evaluation of Candidate Precursors for Chemical Vapor Deposition of Hafnium Diboride (HfB).

Alternative candidate precursors to [Hf(BH)] for low-temperature chemical vapor deposition of hafnium diboride (HfB) films were identified using density functional theory simulations of molecules with the composition [Hf(BH)L], where L = -OH, -OMe, -O--Bu, -NH, -N=C=O, -N(Me), and -N(CH)NH (1-piperidin-2-amine referred to as Pip2A). Disassociation energies ( ), potential energy surface (PES) scans, ionization potentials, and electron affinities were all calculated to identify the strength of the Hf-L bond and the potential reactivity of the candidate precursor. Ultimately, the low (2.07 eV) of the BH ligand removal from the Hf atom in [Hf(BH)] was partially attributed to an intermediate state where [Hf(BH)(H)] and BH is formed. Of the candidate precursors investigated, three exhibited a similar mechanism, but only -Pip2A had a PES scan that indicated binding competitive with [Hf(BH)], making it a viable candidate for further study.