Atomic layer deposition of hafnium dioxide thin films from hafnium tetrakis(dimethylamide) and water

HfO2 films were grown by atomic layer deposition from Hf[N(CH3)2]4 and H2O on Si(100) substrates in the temperature range of 205-400 °C. Around 250 °C, nearly amorphous but dense films grew without marked dependence of their physical properties on the process parameters, such as Hf[N(CH3)2]4 pulse length. Incomplete reaction between adsorbed alkylamide species and water at the lowest temperatures, and thermal decomposition of the precursor at the highest temperatures were the likely reasons to increased impurity content and deterioration the film properties. At intermediate temperatures, films with permittivity of 15-16 and breakdown fields 4-5 MV/cm could be grown. The residual hydrogen, carbon and nitrogen contents in the as-deposited films were marked, exceeding several at.%. Hydrogen content was reduced 4-5 times by annealing procedures.