| 摘要 |
PURPOSE:To enable the detection of various corpuscular beams two- dimensionally at a high sensitivity and with higher resolving power by arranging a thin film layer comprising material with high quantum efficiency on the surface of a metal electrode exposed to the surface of an element. CONSTITUTION:A thin film forming material is preferably high in absorption coefficient having an absorption end in an area of a wavelength shorter than the wavelength of light to be detected and a compound material such as CsI or MgF2 is ideal in an ultraviolet ray area. When the CsI is applied to the surface of an aluminum electrode 1, for instance, connected being exposed to a photodiode structure area 2 formed at a lower layer part at a thickness of about 350Angstrom . the quantum efficiency shows a high value of 20-30% in an ultraviolet area with the wavelength thereof shorter than about 1200Angstrom . The electrode 1 has the quantum efficiency of below about 1% in the wavelength area and the electrode 1 forming a CsI thin film layer improves the sensitivity by more than two order of magnitude. Thus, when a particle beam is applied, a large number of electrons can be released thereby increasing a current value to be read out with an increase in charge value to be accumulated in the area 2.
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