Er-doped Al2O3 thin films deposited by high-vacuum chemical vapor deposition (HV-CVD)

Erbium-doped amorphous aluminum oxide layers deposited on Si or oxidized silicon substrates are promising construction pieces for future monolytic integrated optoelectronics devices. In a novel high-vacuum chemical vapor deposition setup the alumina films are grown with high homogeneity on 4 in. wafers with well controlled growth rate, chemical composition, and high deposition rates of up to 20 nm/min. The HV-CVD applies thermal decomposition of aluminum-isopropoxide with or without additional oxygen as reactive partner gas. Arbitrarily chosen values for different parameters show that deposition works in a wide parameter range and that the chemical composition, the roughness, growth rate, and the resulting index of refraction and optical guiding properties need a systematic study of the working window of the process. Nevertheless optical guiding at 670 nm wavelength is demonstrated and addition of erbium tetramethyl-heptanedionate as erbium precursor results in co-deposition of erbium in the alumina layers.