| 摘要 |
PURPOSE:To analyze the mass with high sensitivity in a short time by radiating/ sputtering primary ions of cesium oxide to the surface of a sample to be analyzed, and sequentially changing the polarity of an ion current detecting electrode which detects generated positive and negative secondary ions. CONSTITUTION:An S-doped GaAs epitaxial layer 12 is formed on the surface of a Cr-doped GaAs substrate 11, thereby constituting a sample to be analyzed. When primary Cs2<+>O ion beams 3 are selectively irradiated onto the sample, the beam 3 collide against the surface of the sample, and at the same time, separated into a Cs8 and an oxygen O7. The Cs8 injects ions to the surface of the electrode and the O7 enters a deep area from the surface of the electrode. First, sulfur S is emitted as a sputtering S<->6, and then Cr is emitted as a sputtering Cr<+>5. In this case, the S<->6 is connected to a secondary ion mass analyzer 24 to enter an ion current detecting electrode 22a which is impressed to a positive potential. On the other hand, the Cr<+>5 enters an electrode 22b which is impressed to a negative potential. In this manner, while the applying polarity is sequentially changed from negative to positive, the negative and positive secondary ions generated at one irradiation of Cs2<+>O ion beams are continuously detected. |
