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Languages : en
Pages : 23
Book Description
In situ, nondestructive surface characterization of thin-film growth processes in an environment of chemically active gas at pressures of several mTorr is required both for the understanding of growth processes in multicomponent films and layered heterostructures and for the improvement of process reproducibility and device reliability. The authors have developed a differentially pumped pulsed ion beam surface analysis system that includes ion scattering spectroscopy (ISS) and direct recoil spectroscopy (DRS), coupled to an automated ion beam sputter-deposition system (IBSD), to study film growth processes in an environment of chemically active gas, such as required for the growth of oxide, nitride, or diamond thin films. The influence of gas-phase scattering and gas-surface interactions on the ISS and DRS signal intensity and peak shape have been studied. From the intensity variation as a function of ambient gas pressure, the authors have calculated the mean free path and the scattering cross-section for a given combination of primary ion species and ambient gas. Depending on the system geometry and the combination of primary beam and background, it is shown that surface-specific data can be obtained during thin-film growth at pressures ranging from a few mtorr to approximately 1 Torr. Detailed information such as surface composition, structure, and film growth mechanism may be obtained in real-time, making ion beam analysis an ideal nondestructive, in situ probe of thin-film growth processes.