HYDROGEN-EFFUSION-INDUCED STRUCTURAL-CHANGES AND DEFECTS IN A-SI-H FILMS - DEPENDENCE UPON THE FILM MICROSTRUCTURE

In order to better understand the effects of hydrogen incorporation an d departure on the defects and the disorder in undoped hydrogenated am orphous silicon (a-Si:H), we performed a comparative study on samples deposited under different plasma conditions. We used a combination of IR absorption spectroscopy, electron-spin resonance, photothermal defl ection spectroscopy, constant photocurrent method, and elastic recoil detection analysis measurements to determine the changes in the defect density and in the disorder, as well as in the hydrogen concentration and bonding modes, after isochronal annealing cycles at temperatures up to 500-600 degrees C. The results, which show a better stability of the bonded hydrogen in the films deposited at high rates, are interpr eted as a whole in terms of specific local hydrogen bonding environmen ts, related to different growth mechanisms.