Chemical vapor deposition of MnxNy films from bis(2,2,6,6-tetramethylpiperidido)manganese(II) and ammonia

Abstract

Thin films of manganese nitride MnxNy are grown by chemical vapor deposition (CVD) using the new precursor bis(2,2,6,6-tetramethylpiperidido)manganese(II), Mn(tmp)2 = Mn(NC9H18)2, with ammonia as a coreactant. This precursor can be prepared in high synthetic yield and has good thermal stability at room temperature; it is one example of a new class of precursors that have the potential to deposit late transition metal nitrides. Under low-pressure CVD conditions, the precursor reacts with ammonia to afford MnxNy thin films in the temperature range of 50–350 °C. The stoichiometric ratio x/y is 2.3–2.5 for all growth conditions used, with oxygen and carbon impurities less than 7 at.% and 1 at.% in the bulk, respectively, as analyzed by x-ray photoelectron spectroscopy. The MnxNy films are x-ray amorphous and are characterized by low root-mean-square surface roughness, 0.4–0.7 nm. Film thickness profiles on trench substrates indicate that growth contains species of both high and low sticking probabilities. The proposed mechanism of film growth is a combination of gas phase and surface transamination between the precursor and ammonia to afford reactive intermediates responsible for film growth.