| 摘要 |
PURPOSE:To promptly meter the thickness of a film on a sample by metering the intensity of an electron beam irradiating the sample and the intensity of the reflected electron beam therefrom to obtain the mean atomic number of the sample having a thin film. CONSTITUTION:A center control circuit 17 controls a sample moving mechanism 16 so that an electron beam from an electron gun 4 may irradiate a Faraday gauge 12 attached to a sample holder 7. The output of the Faraday gauge 12 is stored through an amplifier 13 in a signal converting circuit 11. While maintaining the irradiation current constant, the sample moving mechanism 16 is driven to irradiate an object sample region with the electron beam. The signal converting circuit 11 accomplishes division between the current level of the electron beam reflected from its detector 9 and the current level for sample irradiation stored so that the mean atomic number of the sample is obtained and fed to a film thickness metering circuit 14. In these ways, by introducing the acceleration voltage for sample irradiation and the means atomic number into the circuit 14, the thickness of the thin film 2 of the sample 1 can be obtained and displayed in a display device 15. |
