Atomic layer deposition of Al2O3 thin films from a 1-methoxy-2-methyl-2-propoxide complex of aluminum and water

Al2O3 thin films were grown by atomic layer deposition (ALD) using the novel volatile complex Al(mmp)(3) (mmp = 1-methoxy-2-methyl-2-propoxide, OCMe2CH2OMe) and water vapor in the temperature range of 200-450 degreesC on p-type Si or Ru/SiO2/Si substrates. Al2O3 films were formed at 250 degreesC through the typical self-limiting mechanism of ALD, wherein the saturated growth rate was about 0.6 Angstrom/cycle. The resultant films were amorphous, and the refractive index of the films varied between 1.53 and 1.62, which was dependent on the growth temperature and water pulse length. The aluminium-to-oxygen ratio of the Al2O3 film grown at 250 degreesC was 2:3.1, and the carbon content was 2.4%. With capacitance-voltage measurements of Al/Al2O3/SiO2/Si structures, the dielectric constant of Al2O3 grown at 250 degreesC is evaluated to be 7.7, and the flat band voltage appears at 1.05 V, which corresponds to a negative fixed charge on the order of 10(11)/cm(2). The leakage current density of the Al2O3 films is on the order of 10(-7) A/cm(2) at 1 MV/cm, and the dielectric breakdown voltage is about 6.5 MV/cm.