| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a convenient and precise method and a compact apparatus at a low cost, which measure density of negative ions in plasma. <P>SOLUTION: The apparatus is provided with a discharge plasma device and a negative ion measuring device, and a probe 4 which is a micrometal electrode is inserted into the plasma 3 generated in a plasma container 2 by discharge of a power source 1 for developing the plasma, thereby forming a sheath region around the probe 4. When the probe 4 is biased positively by using a power source 5 for biasing the probe 4 so that the probe potential Vp is higher than the plasma potential Vs, electrons and the negative ions having negative charges are accelerated and collide with the probe 4, and current flows, and a spatter phenomenon arises. A quantity of spatter ΔM is measured by a measuring tool 6, and an inlet flow value Q of the negative ions into the probe is determined from the shape (surface area) of the sheath and the negative ion density n<SB>n</SB>. A relational expression between values Q and n<SB>n</SB>is derived theoretically, and the negative ion density n<SB>n</SB>can be finally determined from measurement results of ΔM. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
