SiH_4射频放电功率耗散机制的光发射研究

Study of Power Dissipation Mechanism of SiH_4 RF Glow Discharge by Optical Emission Spectroscopy

采用OMA - 4 0 0 0测量了SiH4射频辉光放电等离子体的光发射谱 ,研究了其谱线强度随放电射频功率和反应气体流量间的变化关系。发现在放电射频功率增加和反应气体流量升高的过程中 ,其等离子体状态分别发生性质不同的转变 ,这种转变联系到射频功率耗散机制的变化。当反应气体流量增加时 ,电子获得能量的机制由阴极暗区加速转变为等离子体内电场的加热效应 ;而在放电功率升高的过程中 ,离子轰击阴极产生二次电子发射效应导致了光发射谱强度急剧增强的转变。

Optical emissiom spectra of SiH 4 rf glow discharge were measured by OMA-4000.Influence of rf power and gas flow rate on the emission intensity was investigated.It was found that different transitions which were related with the electrical power dissipation took place in the course of increase in rf power and gas flow rate respectively.When gas flow rate increases to a certain value,the 'Joule heating' mechanism by which electrons gain energy occures in the plasma bulk.While rf power increases to a certain value,the secondary electrons generated by positive ions bombarding cathode lead to the enhance of plasma optical emission.