Competing processes on Formation of Negative Ion and Ozone in Recombining Oxygen Plasma

重组氧等离子体中负离子和臭氧形成的竞争过程

• 批准号: 03452284
• 负责人: KADOTA Kiyoshi
• 金额: $ 3.26万
• 依托单位: Nagoya University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (B)
• 财政年份: 1991
• 资助国家: 日本
• 起止时间: 1991 至 1993
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-03452284/
• 关键词: Oxygen Plasma; Recombining Plasma; Negative Ion; Ozone; Atomic Oxygen; Two-Photon Laser-Induced Fluorescence; Mass Spectrometry; 再結合

In this Work, high density oxygen plasma of the order of 10^<12>cm^<-3> has been produced by exciting helicon waves. The plasma was modulated by ON-OFF of RF power, and ionizing and recombining plasmas were produced at the ON and OFF phases of RF, respectively. The aim of the work is to inevestigate comepeting processes on the formation of negative oxygen ion and ozone which would be effectively produced in the afterglow (recombining plasma phase). First, we have investigated behaviors of positive and negative ions by means of time-of-flight mass spectrometry. Negative ions were effectively produced in the afterglow. The O^- ions were mainly produced with a little O_2^- ions. We have also developed two-photon laser-induced fluorescence method to determine absolute density of O-atoms which play an important role in the formation of ozone. It has been found that the degree of oxygen dissociation was about 1% at oxygen of 50mTorr. The decay of O-atoms in the afterglow may be mainly due to processes on the chamber surfases. For ozone, we have tryed to detect it by observing ions of ozone and by laser absorption around 250nm. However we do not yet succeed to do it. It is necessary to improve the detection efficiency for ozone. As a summary, two kinds of diagnostic techniques which are useful to study of basic processes in reactive plasmas could be developed in this research and successfully used for investigating behaviors of ions and radicals in oxygen plasma.

在本研究中，通过激发螺旋波产生了10^<12>cm^<-3>量级的高密度氧等离子体。等离子体通过射频功率的ON-OFF调制，在射频的ON和OFF相位分别产生电离和重组等离子体。研究了负氧离子和臭氧在余辉（复合等离子体相）中形成的竞争过程。首先，我们用飞行时间质谱法研究了正离子和负离子的行为。负离子在余辉中有效产生。主要生成O^-离子，少量生成O_2^-离子。我们还开发了双光子激光诱导荧光法来测定在臭氧形成中起重要作用的o原子的绝对密度。在50mTorr的氧气条件下，氧解离度约为1%。余辉中o原子的衰变可能主要是由腔室表面的过程引起的。对于臭氧，我们试图通过观察臭氧离子和250nm左右的激光吸收来检测它。然而，我们还没有成功地做到这一点。提高臭氧的检测效率是很有必要的。综上所述，本研究可以开发两种有助于研究反应等离子体基本过程的诊断技术，并成功地用于研究氧等离子体中离子和自由基的行为。