Structural evolution during chemical vapor deposition of diamond thin films

In situ phase-modulated ellipsometry was employed to monitor the nucleation and growth processes of diamond thin films fabricated by chemical vapor de position. The effective extinction coefficient (k) at 1.96 eV was used as a basis for dividing the deposition process into intervals. The film growth was aborted at various k values yielding diamond film samples that represen t snapshots of the growth process at different stages. Ex situ characteriza tion of the films was performed using Raman spectroscopy, scanning electron microscopy, and x-ray diffraction. The results indicate that the diamond f ilm deposition process consists of various stages in which the crystalline quality, the net compressive stress, and the relative amount of non-sp(3) c arbon follow different trends. A correlation between the effective k value measured in situ and the film microstructure characterized ex situ was esta blished which enables the monitoring of the diamond film growth process in real time. (C) 2000 American Institute of Physics. [S0021-8979(00)05721-2].