Preparation of nearly oxygen-free AlN thin films by pulsed laser deposition

For preparation of oxygen-free AlN thin films by pulsed laser deposition (PLD), emission spectra of the ablation plume of an AlN target were measured to search for oxygen impurity sources during the growth process. A very sensitive 777 nm emission Line of oxygen was found to be a good process monitor. A new source of oxygen impurity in AlN thin films was found to be the oxidation of the ALN target surface. Its mechanism is discussed and it is shown that simple mechanical abrasion can renew the AlN target. With careful attention paid to preventing all oxygen impurity sources, nearly oxygen-free and stoichiometric AW thin films were grown for the first time by (to the best of our knowledge) PLD. (C) 1998 American Vacuum Society. [S0734-2101(98)01404-3].