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用Langmuir探针对射频(13.56 MHz)感应等离子体进行了诊断,给出了Ar等离子体轴向和径向参数随气压的变化。采用发射光谱测量了等离子体中氩原子的750.3nm谱线强度随气压在轴向的变化,其变化趋势与Langmuir探针测量结果的变化趋势相一致。测量了氩离子的434.8nm谱线强度随气压在轴向的变化并获得了氩离子的434.8nm谱线强度与氩原子的430.0nm谱线强度的比值在轴向三个不同位置的变化。从测得的结果可知:在放电室中上部形成了均匀稳定的高密度等离子体,在靶附近有所降低,在中部以下等离子体密度逐渐变低;在径向6~7 cm以内的区域等离子体参数变化不大,形成了均匀稳定的等离子体,等离子体参数在器壁处变化明显。

Diagnosis of radio frequency induced plasma with Langmiur probe and spectrum

In argon plasma induced by radio frequency of 13.56MHz, radial and axial profiles of plasma parameters have been measured versus pressure by Langmiur probe and axial intensity of Ar spectrum at 750.3nm has been obtained versus pressure using the emission spectrum. The results show that the same diversification appears in both data. Axial intensity of Ar⁺ spectrum at 434.8nm was measured with the pressure, and the ratios of 434.8nm Ar⁺ spectrum intensity to the 430.0nm Ar’s were obtained with pressure in three axial positions. The results indicate that a high density uniform and stable plasma has formed in the middle and at the top of the discharge chamber, its density descends at the target and the plasma density decreases slowly below the middle of the chamber. The plasma parameters change slightly in radial area within 6~7cm, a radially uniform and stable plasma also occurs.