STUDY ON GROWTH-PROCESSES OF PARTICLES IN GERMANE RADIO-FREQUENCY DISCHARGES USING LASER-LIGHT SCATTERING AND SCANNING ELECTRON-MICROSCOPICMETHODS

Citation
H. Kawasaki et al., STUDY ON GROWTH-PROCESSES OF PARTICLES IN GERMANE RADIO-FREQUENCY DISCHARGES USING LASER-LIGHT SCATTERING AND SCANNING ELECTRON-MICROSCOPICMETHODS, Journal of applied physics, 83(11), 1998, pp. 5665-5669
Citations number
24
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physics, Applied
Journal title
ISSN journal
0021-8979
Volume
83
Issue
11
Year of publication
1998
Part
1
Pages
5665 - 5669
Database
ISI
SICI code
0021-8979(1998)83:11<5665:SOGOPI>2.0.ZU;2-#
Abstract
Growth processes of particles formed in germane (GeH4) rf parallel pla te discharges are studied using a laser light scattering and scanning electron microscopic methods. For GeH4(5%)+He, 30 seem, 80 Pa, and a r elatively high power of 40 W (0.51 W/cm(2)), particles begin to be obs erved from a very early time of about 0.13 s after the discharge initi ation around the plasma/sheath boundary near the powered electrode, wh ere emission intensity of Ge atoms is high. This appearance time of pa rticles is extremely early compared to that (about 0.5 s) in silane (S iH4) rf discharges. The localized existence of particles suggests that short-lifetime radicals being generated at a high rate may contribute to the particle nucleation, while little information about reaction r ates for GeHx (x=0-3) radicals is available. After nucleation and subs equent initial growth of particles, they coagulate quickly with one an other, which brings about a growth rate considerably high compared to that for SiH4. Some Ge particles become submicron in size at an early time of 0.3 s and fall to the plasma/sheath boundary near the lower gr ounded electrode. For such a high coagulation rate (growth rate is abo ut 800 nm/s), particles have irregular nonspherical shapes and most of them are agglomerates composed of chains, while they are almost spher ical with a roughness of primary particle size (about 10 nm) for a low coagulation rate (growth rate is about 100 nm/s). Fast appearance of particles for GeH4 discharges also brings about rapid decrease in disc harge voltage and absolute value of self-bias voltage. (C) 1998 Americ an Institute of Physics. [S0021-8979(98)02011-8].