STUDY OF POSTDEPOSITION CONTAMINATION IN LOW-TEMPERATURE DEPOSITED POLYSILICON FILMS

The presence of hydrogen in polysilicon films obtained at low temperat ures by hot-wire CVD and the post-deposition oxidation by air-exposure of the films are studied in this paper. The experimental results from several characterization techniques (infrared spectroscopy, X-ray pho toelectron spectroscopy, secondary ion mass spectrometry and wavelengt h dispersive spectroscopy) showed that hydrogen and oxygen are homogen eously distributed at grain boundaries throughout the depth of the fil ms. Hydrogen is introduced during the growth process and its concentra tion is higher in samples deposited at lower temperatures. Oxygen diff uses along the grain boundaries and binds to silicon atoms, mainly in Si2O groups.