Development of medium energy ion scattering spectroscopy using time of flight method and its application to semiconductor process evaluation

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The purpose of this study is to develop a medium energy ion scattering (MEIS) measurement machine which analyzes a semiconductor surface damage and depth profile of the impurity in the semiconductors.In the 1994 fiscal year, we investigated a palsma induced damage on the semiconductor surfaces by means of semiconductor solid state detector (SSD) for measuring the number and the energy of the scattered ions. A new method to analyze a impurity profile by comparing the experimental and the simulated MEIS spectra was developed.In the 1995 fiscal year, the time of flight (TOF) type ion detector was designed and the performance was simulated. Also the MEIS spectra simulator was improved for the multi-layred structures.In the 1996 fiscal year, the TOF measurement system was assembled and its performance was checked. The two problems of this system became clear. (1) The low chopped beam current. The reason of this was the deflection of the beam axis when the chopping bias (3kV) was applied to … More one of the deflection electrodes (another electrode was grounded). (2) The scattered ions with low energies less than 30 keV were not detectable by the SSD detector due to the electronic noise. In order to improve these problems the following system modifications were carried out. (1) The deflection voltage was applied by two voltage sources (1.5 kV each, opposite direction) connected to each deflection electode. By using this configuration the deflection of the beam axis was suppressed. (2) Multi-channel plate (MCP) detector, which detects the low energy ions (2-50keV) with low electronic noise, was used instread of SSD detector.In the 1997 fiscal year, the ion scattering method was applied to the evaluation of the silicidation reaction of titanium silicides. As a result, it was found that the impurity atoms (Sb) in the Si substrate precipitate at the interface between Si/Ti silicide and Ti silicide/Ti nitiride which act as the passivation layr of the silicide from the oxidation during high tempertaure annealing. Less