LASER ABLATION OF GE IN AN OXYGEN ENVIRONMENT - PLASMA AND FILM PROPERTIES

The growth of Ge oxide films by laser ablation of Ge in an oxygen atmosphere is reported for the first time. Time and space resolved optical measurements of the light emitted by the laser induced plume are performed in order to analyze the plasma reactivity. It is found that the velocity of the plasma species is not influenced by the presence of oxygen up to pressures of 10(-3) mbar, whereas the oxygen content of the films grown in this oxygen pressure range is always below 40%. This low oxygen content is discussed and compared to that obtained with other reactive deposition techniques. In the range of pressures studied, the stoichiometry of the films seems to be mainly determined by the ratio of Ge and oxygen atoms impinging on the substrate rather than by reactions in the plume.