Synthesis of aluminium and gallium fluoroalkoxide compounds and the low pressure metal-organic chemical vapor deposition of gallium oxide films

Aluminium and gallium fluoroalkoxide complexes of formula M (ORf)(3)(HNMe2)[M = Al or Ga; R-f = CH(CF3)(2), CMe2(CF3) or CMe(CF3)(2)] were prepared by reacting the corresponding metal dimethylamide complexes with fluorinated alcohols. The dimethylamine adducts reacted with 4-dimethylaminopyridine to give M(ORf)(3)(4-Me(2)Npy) [M = Al or Ga; R-f = CH (CF3)(2), CMe2(CF3) or CMe(CF3)(2)]. Crystal structure analyses of Ga[OCH(CF3)(2)](3)(4-Me(2)Npy), Ga [OCMe2(CF3)](3)(4-Me(2)Npy) and Al[OCMe(CF3)(2)](3) (4-Me(2)Npy) showed they have distorted tetrahedral geometries. Gallium oxide films were prepared from Ga[OCH(CF3)(2)](3)(HNMe2) and air by low-pressure chemical vapor deposition at substrate temperatures of 250-450 degrees C. Films deposited at 450 degrees C had a composition of Ga2O3.1 by backscattering analysis, an optical band gap of 4.9 eV, and were >90% transmittant in the 300-820 nm region.