AlGaN films grown by chloride-hydride chemical vapour deposition (CH CVD)

摘要

Epitaxial al_xGa_(1-x)N films over all compositional range (0<=x<=) have been grown by CH CVD in Al-Ga-HCl-NH_3 reaction system. alloy composition was reporoducibly controlled by the variation of chloride concentration ratio (AlCl_3 to GaCl) in gas phase. The precision measurements of lattice parameters were performed. Both parameters a and c tend to be higher than the values predicted by Vegard's law. The epitaxial orientation relationships for films grown on sapphire with different orientations are determined. From analysis of absorption spectra the alloy compositional dependence of band gap was determined as following: E_g(eV) chemical bounds3.491 + 2.779x-0.35x(1-x).