Comprehensive characterization of copper oxide atomic layer deposition using water or ozone with enhanced bis-(dimethylamino-2-propoxide) copper delivery

Cu2O and CuO are promising p-type semiconductor materials, which show potential for a variety of applications from photovoltaics to high-T-c superconductors. Atomic layer deposition (ALD) presents an advantageous technique for the growth of copper oxide due to the ability to grow on a variety of substrate materials and geometries with atomic precision in thickness and high uniformity. The work presented here is a comprehensive study on the effect of boost and precursor delivery on the growth of copper oxide films using the same precursor and under the same reactor environment. This is critical to understanding the growth mechanism and properties of ALD grown copper oxide films using the same starting precursor while varying the coreactants. In this study, the deposition of copper oxide is performed using the precursor bis-(dimethylamino-2-propoxide) Cu(II) (Cudmap) and either water or ozone as a coreactant. Keeping the copper precursor pulse constant, CuO films were produced with ozone, while Cu2O films were obtained using water. Through conventional precursor delivery, a saturated growth rate of 0.19 and 0.045 angstrom/cycle is established using ozone and water as coreagents, respectively. In order to enable more efficient precursor delivery, a vapor boost modification was implemented, which doubled the film growth rate to 0.38 angstrom/cycle when using ozone, higher than previously reported. While there was no increased growth rate using the vapor boost with water, the growth rate could be doubled to 0.09 angstrom/cycle by tripling the water dosage. In both cases, the as-deposited films were smoother when implementing a vapor boost and polycrystalline as deposited, which has not been previously observed for Cu2O films grown with Cudmap. From the results here, growth of CuO using ozone is most improved by using a Cudmap vapor boost delivery, indicating Cudmap limited growth, while Cu2O growth is limited by the water dosage.