Glow discharge yam ntxwv ntawm 172nm & 222nm excimer teeb

Glow discharge yam ntxwv ntawm 172nm & 222nm excimer teeb

Tshooj 3 Cov Ntsiab Cai ntawm Plasma Physics

3.5.1 Yam ntxwv ntawm Glow Discharge

Glow discharge yog ib qho kev tso tawm ua ntej thiab ua lub hauv paus rau ntau hom kev tso tawm.

1. Ignition ntawm Glow Discharge

Nyob rau hauv lub tshuab nqus tsev ntim nrog tsuas yog ib tug cathode thiab anode hluav taws xob teb, thaum lub tshuab nqus tsev kawm ntawv qis dua 1 Pa, tom qab txuas lub DC fais fab mov, cov roj yog ionized, thiab glow paug tshwm sim ntawm lub workpiece, nrog rau lub workpiece nto ncig los ntawm ib tug glow txheej. Lub glow discharge tam sim no ceev yog nyob ntawm qhov kev txiav txim ntawm mA / cm², nrog voltage xws li 400 mus rau 5000 V, ua rau nws ib tug siab -voltage, low-tam sim no- paug paug daim ntawv. Thaum lub sij hawm glow tawm, excitation luminescence thiab recombination luminescence phenomena tshwm sim, thiab xim ntawm lub teeb txawv nyob ntawm seb cov roj. Hauv qee qhov kev siv tshwj xeeb, xws li lub tshuab nqus tsev ultraviolet lub teeb ci, cov qauv kev tso tawm zoo sib xws tuaj yeem siv los tsim lub teeb ntawm cov wavelengths tshwj xeeb, piv txwv li, 172 nm excimer teeb lossis 222 nm UV teeb, uas siv cov pa tawm excitation los tsim hluav taws xob excimer.

2. Cathode Fall Region

(1) Muaj peev xwm faib rau pem hauv ntej ntawm Cathode

Nyob rau hauv lub thawv nqus tsev vacuum, ua ntej tso tawm, qhov inter-electrode muaj peev xwm faib tawm yog linear, raws li qhia los ntawm OA₀ hauv daim duab 3-9 [10]. Tom qab tso tawm, qhov zoo ion ceev thiab electron ceev hauv qhov chaw zoo sib xws. Vim yog qhov me me thiab siab tshaj tawm ntawm electrons, lawv txav mus rau lub anode ntawm tus nqi siab; Nyob rau hauv sib piv, zoo ions muaj loj loj thiab txav mus rau lub cathode ntawm tus nqi qis, accumulating nyob ze lub cathode. Qhov zoo ntawm qhov chaw them nqi cuam tshuam cuam tshuam cov hluav taws xob hluav taws xob ntawm cov electrodes, sib npaug rau kev txav lub anode A mus rau cathode C, tsim ib qho anode sib npaug. Qhov hluav taws xob ntawm cov electrodes feem ntau yog faib nruab nrab ntawm cathode thiab qhov sib npaug anode, hu ua cathode poob, raws li qhia los ntawm OA₂ hauv daim duab 3-9. Qhov kev ncua deb ntawm qhov sib npaug anode mus rau cathode yog denoted li d₂, kuj hu ua cathode poob cheeb tsam dav [8].

Qhov sib npaug anode zoo li hloov lub anode mus rau cathode, shortening inter-electrode nrug rau d₂ thiab hloov lub zog hluav taws xob E. Ua ntej roj ignition, lub zog teb E=U_d / d. Raws li qhov kev txiav txim ntawm U_d, cov hluav taws xob tau txais lub zog txaus los ua kom cov pa taws, nkag mus rau tus kheej - kev txhawb nqa tawm theem. Thaum lub sij hawm tso tawm txoj kev loj hlob, vim yog tsub zuj zuj ntawm zoo ions, qhov sib npaug anode maj mus rau lub cathode C, lub ntsiab lus lub anode zoo txav los ntawm txoj hauj lwm A mus rau A₁ thiab ces mus rau A₂. Qhov luv luv ntawm qhov kev ncua deb ntawm cathode thiab anode nce lub zog hluav taws xob, E₂=U_d / d₂. Thaum qhov chaw siab p tsis hloov pauv, lub electron txhais tau tias txoj kev dawb λ_e yog tas li, yog li lub zog hluav taws xob eE₂ λ_e ≫ eE λ_e. Thawj lub zog hluav taws xob eE λ_e txaus rau ionize cov pa roj, thiab inter{17}}electrode voltage U_d tseem tuaj yeem tswj cov txheej txheem tawm. Yog li ntawd, ib zaug cov roj yog ignited, lub inter-electrode voltage cia li poob raws Paschen nkhaus rau U_min, nyob rau hauv uas taw tes qhov kev ncua deb ntawm qhov sib npaug anode thiab cathode yog d_e, thiab cov paug nkag mus rau hauv lub ruaj khov glow paug cheeb tsam. Qhov kev ncua deb ntawm qhov zoo ion txheej txheej mus rau cathode yog d_e. d_e yog yav tas los hais d₂, lub ntsiab lus zoo ion sheath txheej txheej ntawm qhov deb me me d_e los ntawm cathode. Qhov muaj peev xwm poob ntawm cathode thiab anode feem ntau yog faib nyob rau hauv d_e ntau yam, ua rau muaj kev poob qis thiab muaj zog hluav taws xob siab. Cov hluav taws xob thiab ions tau nrawm dua hauv qhov nqaim d_e lub sijhawm no. Qhov zoo ions nrawm nrawm thiab foob pob cathode, zoo siab thib ob electrons los ntawm nws. Cov hluav taws xob nrawm nrawm mus rau lub anode, sib tsoo inelastically nrog cov pa nruab nrab ntawm cov pa roj carbon monoxide hauv lub sijhawm d_e, thaum kawg tsim ib lub tshuab hluav taws xob kom txaus siab rau tus kheej -txhim kho qhov paug tawm thiab tswj cov pa tawm.

(2) Dav ntawm Cathode Fall Region

Thaum lub sij hawm glow discharge, inter{0}}electrode voltage feem ntau poob hauv cheeb tsam cathode poob. Qhov dav ntawm cathode poob nyob ntawm qhov voltage, roj muaj pes tsawg leeg, thiab cov khoom siv cathode. Lub cheeb tsam cathode ntog muaj ib co yam ntxwv: nyob rau hauv unchanged lwm yam dej paug tej yam kev mob, hloov tsuas yog cov roj siab p ua rau lub cathode poob U_c tas li; qhov dav d_e ntawm thaj av cathode poob yog inversely proportional rau p, txo qis raws li lub tshuab nqus tsev℃qis (p nce); thaum cov khoom pd_e tas li, U_c tseem tsis hloov; thaum d=d_e, tsis muaj lwm thaj chaw nyob tsuas yog thaj tsam cathode ntog, tab sis tso tawm tuaj yeem tshwm sim; thaum d<< d_e, discharge extinguishes immediately; if only the inter-electrode distance d is changed, whether moving the cathode toward the anode or the anode toward the cathode, the cathode fall region width d_e remains constant, with only other intervals shortening accordingly. This principle is commonly used for gap shielding of the cathode, with typical gap width of 1~3 mm and gap depth of 8~15 mm.

3.5.2 Lig Glow Discharge thiab Abnormal Glow Discharge

1. Kev sib piv ntawm cov yam ntxwv ntawm ib txwm Glow paug thiab txawv txav glow paug

Hauv kev tsom xam ntawm volt-ampere yam ntxwv nkhaus, qhov sib txawv ntawm qhov paug tawm thiab qhov txawv txav glow tawm tau qhia. Lawv cov yam ntxwv sib piv yog qhia hauv Table 3-5 [10].

2. Ignition Voltage ntawm ib txwm Glow paug

Qhov hluav taws xob hluav taws xob (tawg) qhov hluav taws xob rau lub qhov hluav taws xob zoo li qub yog qhov tsawg kawg nkaus ignition voltage U_min. Yog hais tias cov khoom ntawm qhov kev ncua deb d ntawm cathode thiab anode thiab cov pa roj siab p raws nraim mus rau qhov tsawg kawg nkaus taw tes pd_e ntawm Paschen nkhaus, cov roj paug tawm hluav taws xob yog U_min. Rau cov hlau cathode nrog argon, nitrogen, oxygen, los yog hydrogen, U_min tsuas yog 100 ~ 343 V. Table 3-6 teev cov cathode ntog rau ib txwm ci tawm nrog ntau cov ntaub ntawv cathode thiab gases [2,3,10]. Thaum pib ignition, ci pib ntawm ib cheeb tsam me me ntawm lub cathode nto. Raws li lub zog nce, qhov ci ntsa iab ntawm qhov chaw cathode maj mam nthuav mus txog thaum nws npog tag nrho cov cathode. Thaum lub sij hawm no expansion raws lub cathode, voltage tseem nyob tas li, thiab cathode tam sim no nce nrog lub glow cheeb tsam. Los ntawm Table 3-6, rau ntau yam cathode cov ntaub ntawv, ib txwm glow paug cathode muaj peev xwm nrog argon yog qis dua 165 V. Rau hlau cathode, nrog diatomic gases, nws yog qis dua 343 V.

Feem ntau, qhov kev ncua deb d ntawm cathode thiab anode yog tsau, thiab nws yog ib qho nyuaj rau teem lub tso tawm qhov chaw siab p mus rau qhov tsawg kawg nkaus point ntawm Paschen nkhaus, yog li ntawd lub inter-electrode voltage yuav tsum tau nce los tsim glow paug. Txawm hais tias lub tshuab nqus tsev siab siab siab dua los yog qis dua qhov no, qhov sib cuam tshuam -electrode voltage yuav tsum tau nce mus rau taw tes B mus rau kev hloov ntawm Townsend paug cheeb tsam Ⅱ, los ntawm corona paug cheeb tsam Ⅲ thiab thaum ntxov glow paug cheeb tsam Ⅳ, mus rau hauv ruaj khov glow paug cheeb tsam Ⅴ. Qhov hluav taws xob tawm hluav taws xob poob qis rau taw tes E, qhov twg qhov voltage yog U_min. Hauv lub sijhawm EF, ci ntsa iab maj mam npog tag nrho thaj chaw cathode, qhov hluav taws xob tseem nyob tas li, tam sim no maj mam nce, nthuav tawm cov yam ntxwv ci ntsa iab.

Yog hais tias lub tshuab nqus tsev siab p nyob tas li, thiab qhov inter-electrode nrug loj dhau los yog me dua qhov tsawg kawg nkaus d ntawm Paschen nkhaus, siab dua inter- electrode voltage yog xav tau rau glow discharge, los yog kho electrode nrug yuav ua tau ignition ntawm qis voltage ze rau U_min.

Thaum igniting ntawm voltage siab tshaj U_min, lub zog sab nraud muab lub zog ntau dua rau U_min ignition. Yog tias qhov tseeb pd nyob deb ntawm pd_e, qhov siv hluav taws xob ntau dua, qee zaum dhau 1000 V, nrog rau qhov chaw ua haujlwm ntawm sab laug lossis sab xis ntawm Paschen nkhaus. Vim lub zog siab nkag mus rau lub cathode, ib zaug cov pa tawm ignites, lub cathode nto tam sim ntawd npog nrog ci, nkag mus rau qhov txawv txav glow paug cheeb tsam, tsis tau soj ntsuam maj mam glow expansion ntawm cathode.

3. Cov tsos mob tsis zoo tshwm sim

Tom qab lub cathode nto yog tag nrho npog nrog ci, tawm tam sim no nce nrog nce inter-electrode voltage. Raws li glow tam sim no nce, workpiece nto glow brightness intensifies. Thaum qhov hluav taws xob thiab lub siab raug kho, qhov txawv txav glow tawm mus ruaj khov. Feem ntau cov paug tawm hauv glow discharge ion plating, magnetron sputtering, plasma- txhim kho cov tshuaj vapor deposition, thiab glow discharge ion nitriding ua haujlwm nyob rau hauv thaj tsam glow paug. Cov ntaub ntawv tso tawm no sib piv nrog cov txheej txheem excitation ntawm qee qhov chaw ultraviolet, xws li 222 nm UV teeb, uas tseem cia siab rau cov pa tawm los tsim cov hluav taws xob tshwj xeeb.

3.5.3 Kev faib tawm ntawm ntau yam yam ntxwv ntawm cov hluav taws xob nyob rau hauv Glow Discharge

1. Lub teeb tsis sib xws ntawm cov hluav taws xob nrog cov txheej ci ntsa iab thiab tsaus nti [3-12]

Tom qab cov pa tawm nkag mus rau theem glow discharge, lub ci ntsa iab ntawm cathode mus rau anode tsis sib npaug, thiab kev faib tawm ntawm inter-electrode nqi, peev xwm, hluav taws xob lub zog, thiab lwm yam, kuj yog nonuniform. Daim duab 3-10 qhia cov yam ntxwv sib cuam tshuam ntawm electrode faib hauv glow tawm [10]. Daim duab no qhia meej txog cov qauv kev faib tawm ntawm lub teeb ci (lub teeb siv), muaj peev xwm, lub zog hluav taws xob, lub zog zoo, tus nqi tsis zoo, tus nqi them nqi, qhov ceev tam sim no, thiab roj kub thaum lub sij hawm tso tawm.

2. Yog vim li cas rau tsim ntawm txhua cheeb tsam

Lub ncua sij hawm ntawm cathode mus rau anode yog muab faib mus rau hauv Aston tsaus qhov chaw, cathode glow cheeb tsam, cathode tsaus qhov chaw, tsis zoo glow cheeb tsam, Faraday tsaus qhov chaw, zoo kem cheeb tsam, anode tsaus qhov chaw, thiab anode glow cheeb tsam [10].

Daim duab 3-11 yog ib qho kev nthuav dav ntawm sab saum toj ntawm daim duab 3-10, uas qhia qhov tsis sib xws ntawm lub teeb siv nrog alternating ci thiab tsaus luminescent txheej ntawm electrodes thaum lub sij hawm glow tawm.

Aston tsaus nti: Ions excite electrons los ntawm cathode, thiab raws li cov electrons txav mus rau lub anode, lawv ceev nyob rau hauv lub cathode poob cheeb tsam tab sis muaj tsis txaus lub zog rau excitation luminescence, tsim lub Aston tsaus qhov chaw.

Cathode glow cheeb tsam: Thaum cov hluav taws xob mus txog thaj tsam cathode glow, lawv muaj lub zog txaus los ua kom cov pa roj, ua cov luminescence. Txoj cai luminescence excitation no zoo ib yam li tej lub teeb excimer, xws li 172 nm excimer teeb, uas siv tawm excitation los tsim lub tshuab nqus tsev ultraviolet lub teeb.

Cathode tsaus qhov chaw: Feem ntau cov electrons poob lub zog thaum excitation ua qeeb electrons nrog lub zog hauv qab ionization zog. Tom qab nkag mus rau hauv qhov chaw tsaus nti cathode, lawv tawm sai sai hauv qhov chaw siab zog tsis muaj kev sib tsoo, yog li tsis muaj luminescence.

Tsis zoo glow cheeb tsam: Electrons ceev nyob rau hauv lub cathode tsaus qhov chaw nkag mus rau hauv lub glow cheeb tsam nrog siab zog, ua ntau ionization thiab excitation. Cov cheeb tsam no ua rau muaj kev zoo siab ntau dua thiab rov ua dua luminescence, tsim cov ci ntsa iab heev, ua rau thaj tsam tsis zoo glow lub teeb muaj zog tshaj plaws. Glow xim sib txawv nrog cov pa tawm roj muaj pes tsawg leeg.

Faraday qhov chaw tsaus: Feem ntau cov hluav taws xob poob lub zog hauv thaj av tsis zoo glow, tsis txaus rau qhov tseem ceeb ionization lossis excitation, tsim qhov chaw tsaus.

Cheeb tsam zoo: Electron ntom thiab zoo ion ntom yog ze li ntawm qhov sib npaug, kuj hu ua plasma cheeb tsam. Charged particle ntom yog feem ntau 10¹⁰ ~ 10¹² / cm³, ua tam sim no nyob rau hauv cov pa paug, ua plasma muaj zog conductor. Lub zog hluav taws xob nyob rau hauv kab zoo yog ob peb qhov kev txiav txim ntawm qhov loj me dua hauv cheeb tsam cathode.

Anode cheeb tsam: Electrons absorbed los ntawm lub anode, ions repelled, tsim qhov chaw tsis zoo nqi nyob ze ntawm lub anode, sharply nce lub peev xwm thiab tsim anode muaj peev xwm. Cov hluav taws xob nrawm nrawm hauv thaj av anode tsim kev zoo siab thiab ionization nyob ze ntawm lub anode, tsim anode glow.

Nyob rau hauv lub thawv tso tawm, alternating kaj thiab tsaus tis ntawm glow txheej los ntawm cathode rau anode yog pom. Daim duab 3-12 qhia qhov ci ntsa iab nyob ib ncig ntawm lub workpiece thaum lub sij hawm DC glow tawm ion nitriding, qhia meej meej alternating txheej.

3.5.4 Hollow Cathode Effect hauv Glow Discharge

1. Glow Overlap Phenomenon nrog Ob Lub Cev Plate Cathodes

Cov kev sib tham yav dhau los tau tsom mus rau ib qho - cathode paug tus yam ntxwv. Yog tias ob lub phaj sib luag cathodes muab tso rau hauv lub thawv nqus tsev nrog A raws li anode, lub teeb ci tshwm sim thaum lub zog. Daim duab 3-13 qhia tau hais tias ob qho tib si phaj cathode tso tawm [10].

Thaum cov roj ignition tau ua tiav, ob qho tib si cathodes tsim tawm qhov ci ntsa iab, tsim cov cathode tsaus nti thiab thaj chaw tsis zoo ci nyob ze lawv. Thaum qhov kev ncua deb ntawm ob lub cathodes txaus siab d₁ + d₂> 2d_e, ob qho tib si muaj qhov tsaus ntuj thiab thaj chaw tsis pom kev zoo, sib koom Faraday qhov tsaus ntuj thiab kab zoo. Thaum d₁ + d₂ < 2d_e, ob thaj chaw tsis zoo glow sib tshooj. Cov hluav taws xob tso tawm los ntawm C₁ nrawm hauv C₁'s cathode lub caij nplooj zeeg cheeb tsam thiab decelerate thaum nkag mus rau C₂'s, oscillating ntawm cov electrodes, ua rau muaj kev sib tsoo nrog cov roj molecules, ua rau ntau excitation thiab ionization, nce tam sim no ceev thiab tsis zoo glow siv. Qhov tshwm sim no yog hu ua hollow cathode nyhuv hauv glow tawm [10].

Daim duab 3-14 qhia tau hais tias lub teeb siv hluav taws xob faib nruab nrab ntawm ob daim hlau sib txuas cathode [10]. Ob kab dashed hauv daim duab 3-14 sawv cev ci ntsa iab ntawm txhua lub cathode; Tom qab cov nyhuv hollow cathode, kev siv zog superimpose, nrog kev faib tawm raws li nkhaus M hauv daim duab 3-14.

Yog hais tias qhov tsis zoo glow cheeb tsam ntev nyob rau hauv hollow cathode nyhuv yog d, cathode poob yog V_c, siab yog p, lawv cov kev sib raug zoo yog: pd=f (V_c)

Los ntawm qhov no, ntawm qhov siab dua p, me me inter- cathode deb yog xav tau rau hollow cathode nyhuv; ntawm qis p, qhov deb loj txaus txaus. Yog li, rau kev ruaj khov inter-cathode nrug, seb hollow cathode tshwm sim nyob ntawm qhov siab.

Yog hais tias lub cathode yog ib tug hollow raj, lub puab txoj kab uas hla sib npaug rau qhov kev ncua deb ntawm parallel daim hlau, ua hollow cathode nyhuv ntawm tej lub siab, tsim muaj zog tsis zoo glow ntawm lub raj chaw.

2. Glow Intensity Tom qab tso tawm nrog txawv Cathode nrug

Nyob rau hauv tib lub tshuab nqus tsev chamber, zoo tib yam nqus tsev kawm ntawv, thiab cathode voltage, lub ci siv nws txawv nrog cathode puab thiab phaj nrug, raws li qhia nyob rau hauv daim duab 3-15.