دورية أكاديمية
Plasma diagnosis of reactive high power impulse magnetron sputtering (HiPIMS) discharges
| العنوان: | Plasma diagnosis of reactive high power impulse magnetron sputtering (HiPIMS) discharges |
|---|---|
| المؤلفون: | Bowes, Michael |
| المساهمون: | Bradley, James W, Tu, Xin |
| المجموعة: | The University of Liverpool Repository |
| الوصف: | Reactive HiPIMS discharges have been investigated by employing a selection of plasma diagnostic techniques. Plasma dynamics in a reactive HiPIMS discharge were studied by means of a single Langmuir probe which revealed electron and positive ion densities of the order of 10^17 to 10^18 m^-3 in typical substrate positions, the temporal evolutions of which exhibited a dual-peak structure attributed to the propagation of an ion acoustic wave or the compression and subsequent rarefaction of the process gas caused by the intense 'sputter wind'. The compression phase is also thought to be the cause of the quenching of the effective electron temperature observed during the on-time with the rarefaction phase being responsible for the increase in the effective electron temperature toward the end of the voltage pulse. Negative ion dynamics in the afterglow of a reactive HiPIMS discharge were also studied by means of a Langmuir probe for a range of oxygen partial pressures. The extended afterglow was found to be highly electronegative with the negative ion-to-electron ratio (alpha) at 3 milliseconds after the pulse termination reaching values of almost 400 for the highest oxygen partial pressures. By comparing results to a simple plasma-chemical model, it is speculated that increased negative ion formation occurs for higher oxygen partial pressures due to the increased availability of oxygen metastables that are formed in the active phase. Despite exhibiting a strong correlation, a comparison to the alpha values determined by photodetachment revealed an overestimation by a factor of 8-15 when employing the Langmuir probe method. Furthermore, from photodetachment measurements the O- ion density was observed to peak in the early afterglow at values of the order of 10^17 m^-3. It was also concluded that a negative ion flux of approximately 10^17-10^18 m^-2 s^-1 could be expected at the chamber walls and substrate surface once the plasma afterglow transitions into an ion-ion state, which could have implications for many plasma ... |
| نوع الوثيقة: | text |
| وصف الملف: | application/pdf |
| اللغة: | English |
| العلاقة: | http://livrepository.liverpool.ac.uk/18833/1/BowesThesisCorrected.pdfTest; http://livrepository.liverpool.ac.uk/18833/4/BowesMic_June2014_18833.pdfTest; Bowes, Michael Plasma diagnosis of reactive high power impulse magnetron sputtering (HiPIMS) discharges. [Unspecified] |
| الإتاحة: | http://livrepository.liverpool.ac.uk/18833Test/ http://livrepository.liverpool.ac.uk/18833/1/BowesThesisCorrected.pdfTest http://livrepository.liverpool.ac.uk/18833/4/BowesMic_June2014_18833.pdfTest |
| حقوق: | cc_by_nd |
| رقم الانضمام: | edsbas.ADCF77F4 |
| قاعدة البيانات: | BASE |
| الوصف غير متاح. |