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Optical Emission Imaging and Modelling Investigations of Microwave Activated SiH4/H2 and SiH4/CH4/H2 Plasmasстатья
Информация о цитировании статьи получена из
Web of Science,
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 12 августа 2020 г.
- Авторы: Mahoney E.J.D, Lalji A., Allden J.W.R, Truscott B.S., Ashfold M.N.R, Mankelevich Yu A.
- Журнал: The Journal of Physical Chemistry A: Molecules, Clusters, and Aerosols
- Том: 124
- Год издания: 2020
- Издательство: American Chemical Society
- Местоположение издательства: United States
- Первая страница: 5109
- Последняя страница: 5128
- DOI: 10.1021/acs.jpca.0c03396
- Аннотация: Silicon is a known trace contaminant in diamond grown by chemical vapor deposition (CVD) methods. Deliberately Si-doped diamond is currently attracting great interest because of the attractive optical properties of the negatively charged silicon-vacancy (SiV−) defect. This work reports in-depth studies of microwave activated H2 plasmas containing trace (10-100 ppm) amounts of SiH4, with and without a few % of CH4, operating at pressures and powers relevant for contemporary diamond CVD, using a combination of experiment (spatially resolved optical emission (OE) imaging) and two-dimensional plasma chemical modelling. Key features identified from analysis and modelling of the OE from electronically excited H, H2, Si, and SiH species in the dilute Si/H plasmas include (i) fast H-shifting reactions ensure that Si atoms are the most abundant silicon-containing species throughout the entire reactor volume, (ii) the low ionization potentials of all SiHx (x ≤ 4) species and efficient ion conversion reactions ensure that even trace SiH4 additions cause a change in the dominant ions in the plasma volume (from H3+ to SiHx+), with consequences for electron-ion recombination rates and ambipolar diffusion coefficients and (iii) the total silicon content in the reactor volume can be substantially perturbed by silicon deposition and H atom etching reactions at the reactor walls. The effects of adding trace amounts of SiH4 to a pre-existing C/H plasma are shown to be much less dramatic, but include (i) a Si substrate or fused silica components within the reactor is a ready (unintended) source of gas phase Si-containing species, (ii) OE from electronically excited Si atoms should provide a reliable measure of the Si content in the hot plasma region and (iii) Si atoms and/or SiC2 species are the most abundant gas phase Si-containing species just above the growing diamond surface and thus the most likely carriers of the silicon incorporated into CVD diamond.
- Добавил в систему: Манкелевич Юрий Александрович