Effects of gas-flow sequences on the self-limiting mechanisms of GaAsN films grown by atomic layer epitaxy

• Published in: Thin solid films 2013-07, Vol.540, p.79-83
• Main Authors: Suzuki, Hidetoshi, Sadato, Hajime, Haraguchi, Tomohiro, Yamauchi, Toshihiro, Ozeki, Masashi, Ikari, Tetsuo
• Format: Article
• Language: English
• Subjects: Atomic layer epitaxy; Cross-disciplinary physics: materials science; rheology; Crystal defects; Crystals; Dilute nitrides; Exact sciences and technology; GaAsN X-ray diffraction; Gallium arsenide; Impurities; Lattices; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Other semiconductors; Physics; Precursors; Self-limiting mechanism; Specific materials; Theory and models of film growth; Thin films
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2013.06.018

We adapted the atomic layer epitaxy (ALE) technique to grow GaAsN thin films. The effects of the gas flow sequences used on the self-limiting mechanism (SLM), the N incorporation ratios, and the concentrations of residual impurities were investigated. A pulse of the N precursor (monomethylhydrazine) was added after that of the Ga precursor (trimethylgallium) or the As (trisdimethylaminoarsenic) precursor, which were part of the conventional sequence used for the growth of GaAs films via ALE. If it was noticed that the SLM was in effect, the N precursor was supplied on the Ga- or As-terminated surface (the corresponding sequences and their resulting films are labeled as On-Ga and On-As, respectively). The On-As film exhibited rough surfaces, nonuniform N concentration, and disordered lattices owing to defects. On the other hand, in the case of the On-Ga sequence, GaAsN films with high-quality crystals were grown with the SLM in effect and the concentration of N being a few percent. The concentrations of the residual impurities (C and H) in the On-Ga film were low. This demonstrated that the On-Ga sequence was effective for growing GaAsN thin films on precisely controlled surfaces using the ALE technique. •Atomic layer epitaxy technique was adapted to grow GaAsN films.•GaAsN films were grown with a self-limiting mechanism (SLM) in effect.•Effects of several gas flow sequences on SLM and quality of crystals were studied.