Deposit of plasma chemistry gas phase (PCVD) horniness film becomes velar theory
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1PCVO becomes velar principle and characteristic PCVD is the high-energy electron inside plasma of have the aid of and reaction gas atom, element happening inelastic the dissociation that collision makes or ionization, if pursue 1, produce many deposit series thereby yuan, if atomic, ionic or active radical is round,carry matrix apparently deposit become film. In low-pressure plasma, as a result of the great disparity difference on electron and quality of other discharge particle, the collision odds of the electron in plasma of together with low pressure, neuter particle is very small, the energy that field of dispatches from foreign news agency brings to bear on basically is absorbed by free electron place. Accordingly, low-pressure plasma can regard as by high-energy electron (＜ 20eV) , feebleminded particle (0.
3eV) and neuter gas (about 0.
05eV) composition, the thermodynamic blame that has height balances a gender. By go up knowable, activation of blame balance plasma is replaced heat traditionally the main good point that activation is PCVD, it can make the deposit temperature of matrix is reduced significantly, it is with deposit TiN film exemple, the buildup of plasma the reaction of high temperature gas phase that action makes CVD medium turns low firm plasma into reaction (15) . Gas phase of high temperature of TiCl4+1/2N2=TiN+2C12Td ≥ 1000K(reacts) (plasma of low temperature of 1)TiCl4+2H2+l/2N2=TiN+4HClTd ≥ 530k(reacts) (2) in addition, as a result of the change of means of systematic energy supply, the reaction that also can make cannot undertake below a few hot activation happens below the action of plasma, this is broken through to widen the applied limits of CVD technology is taken, and the kinetic consideration from PCVD, its higher deposit rate also deserves affirmation. Additional, can be in the alveolus of matrix is deposit and have function of layer of good adhesion, film to be able to accuse to wait for an advantage to make us justifiable by the tremendous potential that believes PCVD technology to go up in industrial application. 1.
The activation that catenary of reaction of 2 plasma chemistry reacts in low-pressure plasma basically is the collision action that relies on an electron, and electronic energy distributings limits very wide. Happen in plasma accordingly base yuan reaction is varied. Weakliem  reacts plasma chemistry catenary differentiates for two phase, namely primary response and 2 class reaction. Element and the atom in the electron in primary response and source atmosphere, carrier gas atom, element happening is inelastic collide, cause these elements or atomic to arouse, ionization or decompose form all sorts of active base as ionic as active. Do its react rate gives out by next type: ? Street school longs for Qian Yao of of deep and remote dredge ancienting name for a water catltrop (ε ) for collision cut area, f(ε ) the energy that is an electron distributings function. Among them, if electronic density is enough tall, can think to accord with MaXwell to distributing. Watch 1 gave out a few common primary response and their response rate is constant [20-22] . In 2 class reaction, advocate if exterior place is reached to produce ion in plasma, the element reacts and active radical, molecular reaction, in order to fashion new chemical and active product, watch 2 gave out the 2 class reaction of a few models. In plasma, the buildup as a result of plasma action, all sorts of active with many generation of gas phase lieutenant general base reach active atom, they and matrix surface have taller adherent coefficient, adsorption is in matrix all sorts of apparently active base reach active atom to be in supersaturation condition actually. Accordingly, they in matrix rate of apparently 2 class response becomes control factor, decide rate of velar layer deposit and function  . It is with TiN exemple, to system of TiCl4/N2/H2 reaction deposit, state production has active of ion of TiCl4+ , TiCl3+ , TiCl2+ , Ti+ and TiCl3* , TiCl2* , TiCll* , Ti* among the likelihood that decides velar layer function closely related to reaction base. These are element ion, neuter active radical and aeriform element ask produce ion, the element reacts or reaction of active radical a member forms polymer of complex TixC1y+ , TixC1y* . These are subsequently active base diffuse matrix surface is adsorptive. And the TixC1y* of adsorptive condition decomposes Ti*Cl or Ti below ionic bombard action, and with adsorptive condition NH or with NH+ reaction generates TiN deposit to be in matrix surface, or TixCly+ ionic group bumps matrix to decompose, a dissension solves child adsorption and attend deposit reaction; Another part reflex answers plasma in. Participate in in plasma fall to differ with groovy CVD, atom of group of aeriform element, ionic, active radical, excitation state, element and electron all are in height to be not heat to balance position, cause a large number of neutral by high-energy electron active radical group and ionic group, the mutual reaction between them, make TiN film layer is comparing CVD so low that undertake below much temperature. The experiment makes clear use direct current, radio frequency, microwave and the temperature that shed TiN of pulse PCVD deposit continuously can fall to 400, 500 ℃ [7-14] . The place before 2 research current situation and existence problem are like is narrated, in view of the to reactant incentive means in glow discharge process basically be to rely on an electron to collide, and electronic energy distributings range is wider, because of this plasma base yuan reaction is varied, the interaction of plasma and solid surface is very complex also, this considered to increase very great difficulty into the mechanism of velar process to PCVD. The research that becomes velar mechanism to PCVD at present basically is to use plasma to diagnose a technology, chroma of all sorts of ion in passing pair of plasma, active radical and experimental craft parameter, the deep person of correlation studies between deposit rate and velar layer function, put forward the mechanism becoming film with likely PCVD. Nextpage for example Avni  studied microwave (of the SiCl4 in MW) plasma after decomposing, discovery is active in 2 class reaction base, molecular reaction and ion, molecular reaction mechanism all exists, the occurrence probability cadaver of mechanisms of afore-mentioned two kinds of reaction in putting forward to use plasma will decide graceful the payoff that a kind of mechanism is rate of velar layer deposit, cadaver definition is particle chroma " the product of as sectional as collision σ , p=n σ . Become when I of σ of Ni of ＞ of NR σ R, active radical, molecular reaction mechanism decides response rate; When I of σ of Ni of ＞ of NR σ R, ionic, element.
Reaction mechanism decides response rate. The mutual change that discovers these two kinds of mechanisms as a result suffers the effect of reaction gas composition. If decompose rate and TixCly* to containing H2 and the SiCl4 that do not contain H2,produce rate detect discovery, h2 has ionization of block up SiCl4 to decompose the effect that with stimulative SirCly* active radical produces. So the affiliation of H2 makes active radical, the control element that the element reacts the mechanism makes response rate. The leftover chloric content that this reacts the advantage of the mechanism depends on velar layer but apparent shrinkage. Wait like Ron " " studied radio frequency (when SiCl4 deposit Si3N4 is being used in RF) plasma, use suspension matrix and contrast of ground connection matrix to discover, ground connection matrix because character of radio frequency discharge can make matrix forms one each bias voltage, below bias voltage action, on one hand ionic, molecular reaction is strengthened, on the other hand rich chloric ion bundle strengthen to the bombard action of matrix, gotten remains is chloric be as high as 15wt ％ ; Discover radio frequency power increases at the same time, aeriform ionization action increases, aeriform response rate more mechanism of apt ion a member, make velar layer remains chloric grow in quantity. And below same technology condition, the deposit rate of suspension matrix increases to 11.
H-1(of · of 5 μ M is former only 7.
H-1) of · of 0 μ M, chloric content of velar layer remains only 5wt ％ . Reaction mechanism by ion, the element reacts change is active radical, molecular reaction may be main reason. When the PCVDTiN in TiCl4/N2/H2 atmosphere, the likeness when the action of H2 and PCVDSi3N4. Hilton [the job of 25] shows the remains of TiN film layer that obtains in TiCl4/N2/H2 atmosphere is chloric ＜ 5wt ％ , and get Ti only in TiCl4/N2 atmosphere, layer of Cl compound film, and deposit rate is very low. Can push from this know to react in the 2 class when the PCVDTiN in TiCl4/N2 atmosphere main show is ion, molecular reaction mechanism; And when the PCVDTiN in TiCl4/N2/H2 atmosphere, the likelihood is active radical, molecular reaction is occupied control a position. In recent years, rie [actinograph of 16] consumed chart (OES) technology studied process of TiCl4/N2/H2 atmosphere PCVDTiN is medium, craft parameter and plasma group yuan the relation of spectrum and velar layer structure. The result discovers film grows rate follows the Ti* in gas discharge and N2* the addition of intensity of active radical radiate and increase; Those who follow discharge power input is elevatory, content of the titanium in TiN film is almost changeless (43wt ％ ) , but azotic content increases, chloric content drops. Ishii [actinograph of chart of 17] farther consumed (OES) , 4 extremely mass spectrograph (QMS) considered to be in respectively in TiCl4/N2/H2 and TiCl4/NH3/H2 atmosphere when PCVDTiN film, discharge power input, deposit rate and plasma are medium active radical pH indicator concerns. The result discovers N2, H2 and NH3, the NH in H2 is active base radiation intensity change is apparently distinct. N2, the NH in H2 is active base after raising maximum along with discharge power input, drop suddenly. To this, they think this is likely is as a result of NH active radical is in N2, H2 and NH3, the formation in H2 the mechanism is different cause. Think to be in TiCl4/N2/H2 NH is active base by following ion, control of active radical reaction: N2H of → of 2H+e- (5)N2+H2 of → of N2+e- → N2+2e- (4)H2+e- , NH (9) of → of NH+N (8)N+H of → of N2H+ (7)N2H+e- of H (6)N2+H → sees from afore-mentioned reaction, increase along with discharge power input, n: Molecular ionization and H: The element is decomposed quickly, conduce to NH active pH indicator increasing. And in TiCl4/NH3/H2, NH is active base connect those who pass a member to decompose generation. Namely: N2+H2 (15) of → of NH+NH+H2 (14)NH+NH of → of NH+H+e- (13)NH2+NH2 of → of NH2+H2 (12)NH2+e- of → of H+H+e- (11)H+NH3 of → of NH3+e- → NH2+H+e- (10)N2+e- from reaction type (12) sees, hydrogenous atom conduces to NH3 element decomposing for NH2 group yuan; And NH2 decomposes the active that it is NH further base. And continue to increase discharge power input, criterion NH is active base can react again form N2 and H2, make NH active thereby base chroma drops. In the meantime, research makes clear as a result in deposit of the TiN in TiCl4/NH3/H2 atmosphere rate is older, this basically is chroma of NH radical active increases those who cause. Although the job that wait does not have Rie and Ishii,announce the detail of active radical and matrix surface interaction, but having a bit is collective, namely active radical, the control element that the element reacts the mechanism may be PCVDTiN film. As a result of plasma power input of each groups of discharge of yuan of body of distributinging be deceived inside reactor, direction, discharge, deposit temperature reachs reactor appearance to affect, in last few years, the person such as Morlok [the feasibility that 18] exploration diagnoses OE5 and QMS plasma the technology to apply on the industrial dimensions of bigger reactor, obtained initial effect. They put forward to apply a kind to be able to hang down to be mixed continuously up and down the stereo ray radiation of whirligig appearance, study the plasma chroma that place differs inside furnace distributings, obtain even and high grade horniness film layer thereby through adjusting the craft parameter such as aeriform discharge and direction. Although technology of OES, QMS is in,consider to go up to producing main effect into velar mechanism, but we think from plasma physics and plasma chemistry angle builds PCVD to become velar theory more it is important to show, because although can detect,plasma is diagnosed,pH indicator of all sorts of ion in atmosphere, active radical changes the rule, arrive at matrix when them however when exterior happening deposit reacts, its reaction mechanism how theoretic still be clear about not completely, be opposite especially technology of PCVD horniness film, the energy of life that in matrix surface the majority dispute of aspirant travel balances, originally to answer instead. Accordingly, as the rapid development of PCVD technology, urgent need announces the solid surface in plasma produced what course after all, process rate and action how. Current, this respect already made a few explore work simply, if Veperk is inchoate,the model of statistic of low-pressure discharge plasma that offer thinks, the stability that plasma comprises is by advocate the difference of the time scale that the time scale of chemical reaction process and reactant are the same as electron and child to be the same as environmental interaction decides. Change character, in swap of complex low-pressure plasma energy, if the energy exchange of chemical reaction can regard a relatively independent system as, namely the energy coupling of it and other system is very weak, the energy of chemical reaction accords with Bo ear to this graceful distributing, obtain a stable condition thereby, achieve local and chemical balance in be not a balance namely. Basis to low-pressure plasma the relax of each system pleaseds time estimation, can roll out following and important inequality: In En(16) type of τ of ≤ of Exc of τ of ≤ of Chem of τ of ≤ of γ of τ of ≤ of R of τ of τ T ≤ , the relax comfort time that γ of R of τ T, τ , τ is translation, roll and vibration respectively, τ Chem is the relax comfort time of chemical reaction, τ Exc is the relax comfort time that invokes metastable state, τ En exchanges the relax comfort time of energy for plasma and environment. But distributinging model still needs the active and ionic chroma when wanting to build corresponding and local chemistry to balance position to study further. Taking one with another, PCVD deposit considers to still make progress at present theoretically slow. 3 in looking into PCVD technology to introduce the physical course of glow discharge course of deposit of chemical gas phase, offerred capacious applied prospect for this technology undoubtedly. However, theory of base of deposit of plasma chemistry gas phase and applied basic research are apparent lag studies at becoming velar technology, what will restrict technology of PCVD horniness film to optimize function of the layer that reach film is farther rise. The research that at present PCVD becomes velar theory basically is have the aid of a few advanced plasma diagnose a technology, combinative craft is optimized and velar layer function is evaluated, put forward the likely mechanism that become film. But the process is fashioned in PCVD horniness film in, look substantially function is controlled since exterior reaction. Accordingly, on the exterior reaction mechanism that the stress that near future theory studies should put in PCVD to become film, be like the van material of reaction, of chemical reaction process thermodynamic, kinetic the influence that reachs matrix surface structure to wait for pair of reaction processes and velar layer function. Research a field as the brim of much discipline across, permeate between microtherm plasma physics and plasma chemistry and material science each other, hopeful becomes film in PCVD theoretic obtain greater progress. CNC Milling