Chemical vapor deposition of aluminum and gallium nitride thin films from metalorganic precursors

Abstract

Nearly stoichiometric aluminum and gallium nitride thin films were prepared from hexakis(dimethylamido)dimetal complexes, M2[N(CH3)2]6 (M=Al,Ga), and ammonia at substrate temperatures as low as 200 °C by using low pressure thermal and plasma enhanced chemical vapor deposition (CVD). Both processes gave films that showed little or no carbon (<5 at. %) and no oxygen (<few at. %) contamination, but in all cases there was hydrogen incorporation. The films were highly transparent in the ultraviolet and visible regions. The barrier properties of the aluminum nitride films in a Si/AlN/Au metallization scheme were examined by using backscattering spectrometry. The growth rate of the aluminum nitride films was as high as 1300 Å /min. Overall, the results suggest that M2[N(CH3)2]6 (M=Al,Ga) are promising precursors for low-temperature/low-pressure thermal and plasma-enhanced CVD of group III nitride thin films.