The Influence of Hydrogen Addition on the Chemical Properties of Hydrogenated Aluminum Nitride Films Prepared by RF Reactive Sputtering

Hydrogenated aluminum nitride (AlN:H) films have been deposited on the (100) silicon wafers by the RF reactive magnetron sputtering method with H2 gas in addition to an Ar-N2 gas mixture. Stoichiometric AlN films without oxygen impurities can be prepared by adding 10 % H2 to reactive gas, which is proven by Rutherford Backscattering Spectrometry (RBS). The bonding aspects of Al, N, O and H atoms in AlN:H films have been examined by X-ray Photoelectron Spectroscopy (XPS) and Fourier Transform Infrared (FTIR) to understand the effects of H2 addition. The chemical shift of the binding energies of A1, N and O atoms in AlN:H films from XPS analysis and the change of N-H bonding in FTIR with respect to different partial pressures of H2 gas have been confirmed. The role of H atoms is suggested to facilitate bonding with unbound N atoms in AlN:H films and hinder N-O bonding, thus, reducing oxygen concentration in AlN:H films. Also, the activation energy for the evolution of H2 gas from AlN:H film has been determined to be 0.11 eV/atom through a Kissinger-type analysis by a thermal desorption test using Gas Chromatograph(GC). This result implies that the hydrogen atom in film forms the hydrogen bond.