| 摘要 |
PURPOSE:To improve defect detecting sensitivity by irradiating an accelerated electron beam while scanning it on a semiconductor crystal surface to generate an exciting current, measuring a variation in the current due to the electrically active crystal defect, and then altering a picture signal to a digital signal to store it when the defect is observed as a picture. CONSTITUTION:A video signal from an amplifier 6 is synchronized with a synchronizing signal from a scan synchronizing signal generator 4, converted by an A/D converter 8 to a digital signal, and input to a calculator 9. The calculator 9 stores the digitized video signals at each one screen, converts the to analog signals by a D/A converter 10, input to an intensity modulation input of a CRT 7, a synchronizing signal from the generator 4 is input to the synchronous input of the CRT 7, and displayed as a calculated picture image. Thus, a large difference of an S/N ratio when N pieces of the stored pictures are stored is generated from S/N ratio when each screen is displayed on the CRT without storing, and the crystal can be accurately evaluated for its characteristics. |
