| 摘要 |
PURPOSE:To supply the ion beam of the desired raw material stably and with high density by forming a means emitting electrons with a low-temperature type electron emitting element. CONSTITUTION:A low-temperature type electron emitting element is used as an electron beam generating source. The electron beam generating source is constituted of the MIM (metal M1-insulator I-metal M2) type electron emitting element and practically formed with an Al-A2O3Au thin film. The voltage V larger than the work function phim of the metal M2 is applied across the metals M1 and M2, and electrons having the energy larger than the vacuum level among the electrons tunneling through the insulating layer I are emitted from the surface of the metal M2. The thermal decomposition quantity of raw material grains at an ionizing unit section 10 caused by the heating by the electron emission source is thereby reduced, and the ionization of the desired chemical species can be performed efficiently and stably.
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