Abstract
Alternative candidate precursors to [Hf(BH(4))(4)] for low-temperature chemical vapor deposition of hafnium diboride (HfB(2)) films were identified using density functional theory simulations of molecules with the composition [Hf(BH(4))(2)L(2)], where L = -OH, -OMe, -O-t-Bu, -NH(2), -N=C=O, -N(Me)(2), and -N(CH(2))(5)NH(2) (1-piperidin-2-amine referred to as Pip2A). Disassociation energies (E (D)), 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 E (D) (2.07 eV) of the BH(4) ligand removal from the Hf atom in [Hf(BH(4))(4)] was partially attributed to an intermediate state where [Hf(BH(4))(3)(H)] and BH(3) 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(4))(4)], making it a viable candidate for further study.