Kev sib cuam tshuam ntawm excimer UV teeb thiab arc tawm

Kev sib cuam tshuam ntawm excimer UV teeb thiab arc tawm

3.6.1 Yam ntxwv ntawm Arc Discharge

Thaum qhov ceev tam sim no nyob rau hauv qhov txawv txav glow tawm los ua siab heev, ions hnyav heev rau ntawm lub cathode nto, ua rau lub zos cua sov ntawm lub cathode thiab emission ntawm ib tug loj tus naj npawb ntawm thermionic electrons. Qhov no txo ​​qhov chaw tsis kam, ua rau muaj kev poob qis hauv inter-electrode voltage, thiab tam sim no nce tam sim no, hloov lub ci tawm mus rau hauv arc tawm. Table 3-8 piv cov yam ntxwv ntawm arc tawm thiab glow tawm [10].

3.6.2 Hom Arc Discharge

Classification los ntawm Discharge Voltage(1) Tsawg-pressure arc tawm: Arc tawm ntawm cov roj siab hauv qab 100 Pa, tseem hu ua lub tshuab nqus tsev arc. Qhov kub ntawm electron nyob rau hauv arc kem nce mus txog 10⁴–10⁵ K, thaum qhov hnyav particle kub yog me ntsis siab dua qhov kub ntawm ambient, tsim ib tug tsis-equilibrium plasma. Hom arc no feem ntau ua ke nrogexcimer UV teebrau auxiliary excitation los txhim kho plasma kev ua si thiab cov tshuaj tiv thaiv efficiency. (2) High-pressure arc tawm: tshwm sim hauv cov pa roj lossis vapor arcs ntawm qhov siab tshaj 100 Pa; arcs ntawm atmospheric siab yog siab -siab arcs. Lub arc kem yog tus yam ntxwv ntawm thermal sib npaug ntawm cov electrons, zoo ions, thiab nruab nrab roj atoms los yog molecules, nrog roj kub txog 4000-20000 K nyob rau hauv ib tug constricted arc kem.

Classification los ntawm Formation Mechanism of Arc DischargeRaws li daim ntawv ntawm arc tawm, nws tau muab faib ua thermionic arc tawm thiab txias cathode teb -emission arc tawm, uas yog qhia nyias hauv qab no.

3.6.3 Thermionic Arc Discharge

Thermic Emission [10,13,14]Thaum cov hlau saum npoo kub siab heev thiab lub zog hluav taws xob ntau dhau ntawm kev ua haujlwm, cov hluav taws xob khiav tawm ntawm lawv cov ntawv cog lus thiab raug tso tawm. Thaum lub thermionic tam sim no ceev yog siab, nws tsim ib tug thermionic cathode arc paug. Tus kheej - txhawb nqa thermionic cathode arc tawm yog tswj los ntawm kev ruaj khov thermionic emission los ntawm cathode. Cov hlau refractory nrog kub coefficients tsis kam, xws li tungsten, molybdenum, los yog tantalum, feem ntau yog siv rau thermionic emission. Table 3-9 [10] teev cov kev sib raug zoo ntawm cov thermionic emission ceev thiab kub rau tantalum; qhov siab dua qhov kub, qhov ntau dua qhov thermionic emission ceev.

Thermionic emission density yog xam los ntawm cov kab zauv hauv qab no: J=AT2e−X/kT J=AT^2 e^{-X / kT} J=AT2e−X/kT qhov twg:

JJJ - Thermionic tam sim no ceev (A/cm²);

AAA - Thermionic emission tas li ntawm cov khoom [A/(cm²·K²)];

TTT - Cathode khoom kub (K);

XXX - Electron ua haujlwm muaj nuj nqi (eV);

kkk - Boltzmann tas li, k=1.38 × 10−23k=1.38 \\times 10^{-23}k=1.38 × 10−23 J/K.

Los ntawm qhov sib npaug, txij li AAA, XXX, thiab kkk yog qhov tsis tu ncua rau cov khoom siv, cov thermionic emission ceev los ntawm cov khoom siv cathode nce nrawm nrog qhov kub thiab txias.

Cov khoom siv thermionic emissionCov khoom siv thermionic emissions hauv ion plating tshuab suav nrog cov hlau refractory xws li tungsten, molybdenum, tantalum, thiab lanthanum hexaboride [11]. (1) Refractory metals: Tungsten ua haujlwm ntawm qhov kub thiab txias ntawm 2600-2900 K, feem ntau hauv daim ntawv filament; tantalum ntawm 2400-2800 K, feem ntau nyob rau hauv daim ntawv tubular; molybdenum ntawm 2200-2500 K, feem ntau nyob rau hauv filament, ntawv, los yog tubular daim ntawv. (2) Lanthanum hexaboride: Ib qho ceramic- hom thermionic emitter nrog lub thermionic emission kub nyob ib ncig ntawm 1700 K (qis dua tantalum hlab) thiab siab emission tsis tu ncua, tso cai rau thermionic emission ntawm qis kub. Hauv kev siv tswv yim, thaum lanthanum hexaboride siv los ua cov khoom siv emission, nws kuj tuaj yeem ua ke nrog UV hluav taws xob los ntawm excimer UV teeb kom ua kom zoo dua electron emission efficiency nyob rau hauv qis - qhov kub thiab txias ib puag ncig.

Hollow Cathode Arc Discharge(1) Cov xwm txheej rau hollow cathode arc tawm: Daim duab 3-25 qhia lub hauv paus ntsiab lus ntawm hollow cathode arc tawm [10]. Lub raj tantalum ua haujlwm raws li rab phom cathode hollow, txuas nrog lub davhlau ya nyob twg tsis zoo ntawm arc fais fab mov, thaum lub anode muab tso rau hauv lub txheej txheej thiab txuas nrog lub davhlau ya nyob twg zoo. Lub arc fais fab mov muaj ib qho kev sib txuas ua ke ntawm qhov hluav taws xob hluav taws xob thiab lub zog hluav taws xob. Thaum qhia cov roj argon, UV irradiation los ntawm excimer UV teeb tuaj yeem txhawb nqa cov pa roj ionization pib, txo qhov hluav taws xob hluav taws xob mus txog 1000 V, igniting glow discharge nrog tam sim no ncav cuag 30-40 A. Cov khoom siv hluav taws xob ruaj khov ua haujlwm ntawm 20-70 V nrog arc tam sim no ntawm 80-300 arc tam sim no los ntawm cov pa roj carbon monoxide. cathode arc tawm ntawm lub tshuab nqus tsev nyob ib ncig ntawm 100 Pa.

Ua ntej, qhov hluav taws xob siab ntawm ntau pua volts ignites cov roj, ua hollow cathode glow paug. Vim lub hollow cathode nyhuv nyob rau hauv glow paug, qhov tam sim no ceev nyob rau hauv lub hollow cathode yog siab heev, tsim ib tug loj tus naj npawb ntawm argon ions uas bombard lub tantalum raj phab ntsa. Lub tantalum raj kub nce siab tshaj 2100 degree, emitting thermionic electrons. Cov hluav taws xob los ntawm cov pa tawm thiab cov hluav taws xob thermionic ua ke ua ib qho siab -cov khoom siv hluav taws xob ceev coj mus rau lub anode, cua sov lub anode thaum tuaj txog. Hollow cathode arc tawm yog tus kheej - txhawb nqa thermionic cathode arc tawm.

(2) Kev faib tawm kub ntawm lub hollow cathode: Qhov kub ntawm qhov kev faib tawm tom qab ruaj khov hollow cathode arc tawm yog qhia hauv daim duab 3-26 [10]. Lub hauv paus ntawm tantalum raj, txhawb nqa los ntawm cov dej-txias clamp, muaj qhov kub qis tshaj plaws; qhov qhib kawg ntawm lub raj yog me ntsis txias vim yog thermal tawg; Qhov kub siab tshaj plaws tshwm sim ntawm qhov deb lll (li 20 mm) los ntawm qhov qhib kawg.

(3) Lub zog poob hauv hollow cathode arc: Daim duab 3-27 qhia lub zog poob hauv hollow cathode arc [10], qhov twg WtotalW_{\\text{total}}Wtotal yog tag nrho lub zog ntawm lub hollow cathode arc, thiab WanodeW_{\\text{anode}}Wanode thiab WcathodeW_ yog cov ntsiab lus lub anode thiab cathode, feem. Daim duab qhia tau hais tias, ntawm qhov sib txawv hollow cathode tawm tam sim no, feem ntau ntawm lub zog yog dissipated ntawm lub anode, nrog tsawg heev ntawm cathode. Nyob rau hauv hollow cathode ion plating, lub anode yog ib tug hlau ingot muab tso rau hauv ib tug crucible, thiab li ntawm 60% ntawm lub hollow cathode phom hwj chim yog siv rau cua sov thiab evaporating cov hlau.

Kub Filament Arc Gun DischargeLub arc paug uas tsim los ntawm ib tug kub filament arc phom kuj belongs rau thermionic arc paug hom [10,13,14]. Cov phom kub filament arc yog ntsia rau saum lub txheej chamber, nrog tungsten thiab tantalum filaments hauv rab phom lub cev. Cov phom yog nruab nrog lub tshuab hluav taws xob cua sov thiab lub zog arc. Tsawg-voltage, siab- cov khoom siv hluav taws xob tam sim no ua rau cov tungsten thiab tantalum filaments mus rau qhov kub thiab txias, emitting siab - ceev electrons. Nyob rau hauv kev xyaum, auxiliary irradiation los ntawm ib tug excimer UV teeb tuaj yeem ua ntej - qhib hluav taws xob rau ntawm qhov chaw filament, ua kom cov pa hluav taws xob pib ua ntej. Tom qab qhia cov roj argon rau hauv cov phom kub filament arc thiab txuas cov khoom siv hluav taws xob arc, qhov siab -density thermionic electrons ionize cov roj argon, tsim cov khoom siv hluav taws xob ntxiv. Lub siab -density thermionic electrons thiab electrons los ntawm argon tawm converge mus rau hauv arc electron kwj coj mus rau lub anode.

3.6.4 Txias Cathode Arc Discharge

(1) Cold field emission [10,13,14]: Positive ions accumulate in front of the cold cathode, form a dipole layer (tseem hu ua plasma sheath) ntawm ions thiab cathode. Nyob rau hauv thawj theem ntawm txias teb emission, ib tug excimer UV teeb yuav pab tau los ntawm kev txhim kho tus nqi ntawm zoo ion tsub zuj zuj, accelerating nce nyob rau hauv sheath teb zog. Thaum lub zog ntawm lub plhaub tau nce mus txog 10⁷–10⁸ V / cm, kev tawg tshwm sim, emitting ib tug loj electron tam sim no, hu ua teb emission. Qhov txias cathode arc tawm feem ntau siv qis- melting{10}} taw tes hlau xws li tooj liab, nyiaj, lossis titanium ua cov khoom siv cathode. Tag nrho cov cathode tseem txias, tab sis lub arc ua rau lub zos evaporation ntawm cov khoom cathode, nce vapor siab thiab shortening txoj kev dawb huv rau 10⁻⁸–10⁻⁴ cm.

(2) Tus kheej-kev txhawb nqa cov txheej txheem ntawm qhov txias txias- emission arc tawm: Cov cheeb tsam cathode hauv qhov chaw txias- emission arc tawm me me (10⁻⁶–10⁻⁴ mm²). Raws li cov ntaub qhwv tawg, micro- thaj tsam tam sim no ceev nce mus txog 10⁶–10⁸ A / cm², nrog lub zog ceev ntawm (1–3) × 10⁷ W / cm². Evaporated hlau atoms yog ionized rau hauv zoo ions nyob ze ntawm qhov chaw arc. Cov ions no txuas ntxiv mus rau pem hauv ntej ntawm lub hom phiaj, tsim ib txheej dipole uas txhawb nqa lub arc tawm.

(3) Kev txav ceev ceev ntawm qhov chaw txias-emission arc ntawm lub cathode nto: lub cathode nto tsis sib xws, nrog protrusions los ze zog mus rau qhov zoo ion accumululation txheej muaj ntau dua hluav taws xob teb zog, nyiam ua teb emission thiab arc [9]. Tom qab cov khoom protruding yog rhuab thiab evaporated, tsim ib lub qhov, lub zog teb txo, extinguishing arc; lwm protrusion ces pib teb emission, txuas ntxiv mus evaporate txheej hais. Yog li, qhov chaw txias -emission arc txav ceev ceev hla lub cathode nto ntawm tus kheej - scanning.

(4) Ci ntsa iab arc me ntsis ntawm qhov chaw cathode: Thaum lub caij txias txias -emission arc tiam, qhov tawg ntawm qhov cathode yog me me heev. Hauv cheeb tsam me me no, ions nkag mus rau hauv cathode, electrons raug tso tawm, thiab cov luminescence recombination dav ua rau cov pob zeb ci ntsa iab. Raws li lub arc txav nrawm, nruam txav ntawm arc me ntsis yog pom ntawm lub cathode.

(5) High plasma density from cold field-emission arc: With a me breakdown area and high current density, evaporated atoms have a high probability of collision ionization with the high -cov electron ceev ceev, tsim ntau ions thiab electrons. Yog li, qhov chaw txias -emission arcs tsim siab -plasma ceev.

3.7 Lub luag hauj lwm ntawm Charged Particles

Cov khoom uas raug them hauv cov pa tawm muaj xws li ions thiab electrons, uas txav mus rau qhov sib txawv ntawm cov electrodes hauv qab hluav taws xob. Cov teebmeem tseem ceeb thaum ions ncav cuag cathode thiab electrons ncav cuag lub anode yog tham hauv qab no [2,3,7,10,12,14].

3.7.1 Lub luag haujlwm ntawm Ions

Ib tug series ntawm lub cev thiab tshuaj phenomena tshwm sim thaum ions bombard lub cathode nto. Daim duab 3-28 qhia txog ntau yam teebmeem uas tsim los ntawm ion bombardment ntawm lub cathode nto. Cov nyhuv synergistic ntawm excimer UV teeb tuaj yeem txhim kho cov teebmeem ntawm lub cev thiab tshuaj lom neeg, xws li nce sputtering tawm los thiab txhim kho uniformity ntawm qhov chaw hloov kho.