Impact of substrate temperature and film thickness on the interfacial evolution during atomic layer deposition of HfO2 on InP

The effects of both the deposition temperature and the HfO2 film thickness on the interfacial layer (IL) evolution were studied when tetrakis(ethylmethylamino)hafnium and H2O based atomic layer deposition (ALD) was performed on InP substrates. While the self-cleaning effect resulted in an IL-free structure after formation of ∼2 nm thick HfO2 at 200 °C and 250 °C, substantial IL growth occurred at 300 °C, probably due to simultaneous InP oxidation. Following further growth to ∼8 nm at 300 °C, the IL was almost removed and, in particular, a significant In incorporation into the HfO2 film was observed, which was attributed to IL decomposition and subsequent out-diffusion of the constituent elements. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)