Influence of native silicon oxides on the growth of GaN nanorods on Si(001)

Influence of native Si oxides on the growth of GaN nanorods on Si(001) substrates have been investigated. At the initial stage of GaN growth on clean Si(001) substrates at 450 °C, (2x1) reflection high‐energy electron diffraction patterns immediately change into halo patterns, indicating growth of amorphous materials. The cross‐sectional transmission microscopy observation and secondary ion mass spectroscopy measurement reveal that there exists an amorphous Six Ny layer at the GaN/Si interface. This provides the evidence that during the initial growth of GaN on clean Si substrates with out native oxides, nitridation of Si takes place to form amorphous Six Ny as well as GaN. The structural properties and surface morphologies of these interfacial layers affect GaN nanorod growth. By contrast, native oxides act as a mask against nitridation of Si substrates. Since plasma‐activated nitrogen mainly reacts with Ga to form GaN, GaN growth always proceeds under a desired N‐rich growth condition. As a result, GaN nanorods are uniformly grown on Si(001) with native oxides. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)