| 摘要 |
PURPOSE:To decrease the amount of accumulated charges and to prevent a silicon oxide film from being broken by using a power source to superpose a toothed voltage on a DC acceleration voltage which accelerates ions so that ion flux can be radiated over a wide area of a semiconductor substrate. CONSTITUTION:Ions produced in an ion source 1 are extracted by an electric field which is generated by a DC acceleration power source 3 interposed between the ion source 1 and an extraction electrode 2, and they are made incident on a mass spectrometric electromagnet 4 so as to become an ion flux 5, and they are radiated on a semiconductor substrate 7 on a rotating plate 6. When a toothed wave voltage is superposed on a DC acceleration voltage by a toothed wave power source 8, this ion flux is scanned between an ion flux 5A and an ion flux 5B so as to irradiate a wide area of the semiconductor substrate 7. A frequency of the toothed wave voltage is made to be several hundreds of Hz, because the ion flux is moved fast at a tangent speed of the rotating plate 4. Thus, charges can be prevented from being accumulated and a silicon oxide film can be prevented from being broken.
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