Combinatorial high vacuum chemical vapor deposition ͑HV-CVD͒ of mixed HfO 2 -Nb 2 O 5 thin films has been demonstrated to yield amorphous layers at substrate temperatures where individually deposited pure HfO 2 and Nb 2 O 5 films are polycrystalline. Spectroscopic ellipsometry of the films shows that adding HfO 2 to Nb 2 O 5 improves the transparency of the films while still maintaining a high refractive index. Atomic force microscopy measurements show that the root-mean-square surface roughness of the films is about 1.2 nm.

The deposition of amorphous alumina (Al2O3) films on four inch wafers with high deposition rate (up to 50 nm/min) by an advanced HV-CVD technique is discussed. Amorphous nature of the films is confirmed by X-ray diffraction. Refractive index of the deposited alumina can be adjusted in the large range (1.3-1.62@633 nm) by varying the substrate temperate during the deposition. The films are highly transparent. The density and stoichiometry of the deposits are also influenced by deposition conditions. Presence of -OH groups is observed in some cases.

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