AN INVESTIGATION ON THE FREQUENCY CHARACTERISTICS OF THE RF DISCHARGE IN AR-HG MIXTURES

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Submitted on 1 Jan 1979

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AN INVESTIGATION ON THE FREQUENCY CHARACTERISTICS OF THE RF DISCHARGE IN

AR-HG MIXTURES

Hsu Hsueh-Chi

To cite this version:

Hsu Hsueh-Chi. AN INVESTIGATION ON THE FREQUENCY CHARACTERISTICS OF THE RF

DISCHARGE IN AR-HG MIXTURES. Journal de Physique Colloques, 1979, 40 (C7), pp.C7-225-C7-

226. �10.1051/jphyscol:19797111�. �jpa-00219082�

JOURNAL DE PHYSIQUE Colloque C7, suppZ6ment au n07, Tome 4 0 , J u i l l e t 1979, nage C7- 225

AN INVESTIGATION ON THE FREQUENCY CHARACTERISTICS OF THE RF DISCHARGE

IN

Hsu Hsueh-Chi.

I n s t i t u t e of Electric Light Source, Fudan Unive

( 1 ) According t o t h e modes of e x c i t a t i o n , t h e

e l e c t r @ d e l e s s discharge may be oontenieritly d l r i d e e i n t o two k i n a s : E discharge end H discharge. These two t y p e s of discharges may e x i s t sixultaneously I n t h e .rf ' d i s c h a r g e s . I n weakly Ionized plasma, t h e rf e l e c t r i c f i e l d may be many t e n times g r e a t e i 'than the' t ~ r o i d a l elec- t r l c f i e l d .

t h e B discharge may be covered up by t h e E dis0harge,especla- I l y a t t h e breakdown s t a g e . It i s d i f f i -

c u l t t o d i s t i n g u i s h them experimentally.

Therefore, they were seldom d i s c u s s ~ d . We hare ,suggested a method of d o t e m i n l n g t h e frequency r n r l a t i e n

a i s t ingulsh and i n v e s t i g a t e 0n t h e r f dischclrgea.

According t a t h e r a r i a t i o i z ef frequency, we m y utlderstafid t h e e f f e c t s of E dia- charge and H discharge during t h e rf discharges.

( 2 ) fer t h e s e reasons,

study t h e breakaewn, a r c i n g and maintezianca

t h e r f discharge and t h e r a r l a t l @ n of i t s frequency, The discharge i s c r e a t e d by maximum -Bagnet i c e x c i t a t i o n In m-EG mix-

t u r e s . The r f source I s a t m s i s t e r push- p u l l pewer e s c i l l a t 6 2 ; whgrne pawer cdnsum- t l o n i s 9s Watts. The discharge chamber l a

bpheribalglass bulb 100 mm i n dla- metee. 'The disdhbrge brtlb and

source a r e shbwn in Fig.1,

r s i t y , Shanghai, China.

P". C--Hj>

FJ. 2

Frem Flg.3, we c m express t h e r e l a t i e a s between

and PA,

where

i s t h e p r e s s u r e ef Argon,

a d c d6paPld upon t h e discharge pcawer and i t s frequency,

( 3 ) The f a c t t h a t t h e v a r i a t i o n of f r e - quency depends on t h e mechnnism

t h e r f d i s c h a r g e may be analysed a s f s l l e w s . A t breakdswn, due t o t h e E discharge, t h e

We measure t h e rf v o l t a g e s a c r e a s $he Induction c o i l i n o r d e r - t @ determine t h e breakdown voltage-VB ,

a r c i n g v o l t a g e

and maintainable vol- t a g e V , a t v a r i o u s p r e s s u r e s of Ar, We a l s o record t h e v a r i q t i o n of t h e frequ- ency d u r i n g t h e d i f f e r e n t s t a g e s of

abarge. The r b s f i l t s a r e shown i n Table 1, Fig.$ and 3'5i3.*3*TBB&Z.

I .

.

.

capacity ef t h e c l r c u i t condenser would increase. This Increase lewers t h e discha- rge frequency. Oa &he o t h e r hlnd, af t o r a r c i n g , t h e r e e x i s t 8 t h e plnsma, whore d i e l e c t r i c c o n s t a n t may cause a change In c a p a c i t y of t h e c i r c u i t cendenser. The inductance r e f l e c t e d by t h e discharge int@ t h e c l r a u i t

reduces th.e t o t a l e f f e c t i v e inductance e f t h e c i r c u i t , and t h e pewer abserbed by t h e discharge fig- n i f i c a n t l y i n c r e a s e s t h e e f f e c t i v e a e r i e s r e s i s t a n c e s

t h e c i r c u l t . The r e s u l t i s a n i n c r e a s e e f t h e frequency af

cescillatcsr in i t s leaded c o n d i t i e a . It

be proved t h a t a t .arcing, t h e i n c r e a s e of t h e frequency I s

dfn

= 1 5

--

^f

2 I + Ra/(znf~,J'

Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:19797111

where f i s t h e discharge frequency, ^R i s t h e e f f e c t i r e r e s i s t a n c e of tkie plasma,

K= M''/L,L,

, ^M i s t h e mutual inductance

of primary c i r c u i t and secondary plasma, L I _and L2 a r e t h e inductianceo of primary c i r c u i t . and secondary plasma r e s p e c t i v e l y .

Frsm t h e abore equation, we con s e e t h a t t h i s i n c r e a s e in frequency can nere'li be n e g a t i r e . Therefere,-we may understand c l e a r l y t h a t both E and

discharges e x i s t i n s u r maximum magnetic excited

discha- r g e s , The brenkd~von

t h e discharge i s caused maiAly

t h e rf e l e c t r i c f i e l d (E d i s c h a r g e ) ; hswerei?, t h e a r c i s e s t a b l i s h - ed by t h e r i n g discharge inducbd by t h e a l t e r n a t i n g magnetic f i e l d (H discharge.),

Frsm Pig,2, we can s e e t h a t when t h e a r c

i s e s t a b l i s h e d , t h a r a l t a g e cress t h e in- duction c s i l may b e lowered suddendly t o t h e maintenance r a l t a g e , whose magnituda should

r e l a t e d with t h e power coupled t o t h e

d i r e c t l y . There i s a m a x i m

@f %he maintenance r a l t a g e a t t h e p r e s s u r e ef R r between

te

Im t h i n regien i t p r o r i d e s t h o

cenrerston e f f i c i e n y frem t h e

8enrc.a t e t h e plasma.

The abore r e o u l t s en t h e frequency

t i o n sf t h e rf discharge may

used t o study t h e mechanism of t h a t

and t o o p t i m i z e t h e dQsign ef t h e e l e c t r o d r - l e s s l i g h t seurcas.

REFEREETCES

(1) G'.Praicis: Ieriizatfon Phenemena i n Gbses:1960

( 2)

H.U.Eckert: Prec.

ICPIG,1959,

11 A 320