 the equipment used, it would seem difficult to take the risk of forming silica powder, it being known that, in places, for reasons of homogeneity of the mixture, this limit of 0.8% may be exceeded. PA1 preparing the final gaseous mixture (which thus contains a carrier gas, for example a neutral gas or alternatively a mixture of a neutral gas and of a reducing gas such as hydrogen, an oxidizing gas and a silane), in at least two stages, by first preparing a gaseous mixture, which can be described as "primary", which contains a neutral gas and the silane, the silane content in the primary gaseous mixture being below the self-ignition limit of the silane in air; and PA1 the primary gaseous mixture thus formed is mixed with a stream of the carrier gas and, if appropriate, a stream of the oxidizing gas (depending on the residual content of oxidizing gas in the carrier gas), in proportions which make it possible to obtain the required final mixture, the addition of the primary mixture stream or of the oxidizing gas stream, to prepare this final mixture, being carried out under dynamic conditions.
By way of example, the standard use of mass flow controllers employing a capillary seems very risky, even below the concentration limit put forward in this article by K. Strater.
In a way which is consistent with these results, mention may be made of another example from the literature, by M. L. Hammond and M. H. Bowers (which appeared in Transactions of the Metallurgical Society of AIME, March 1968), which relates to the CVD deposition of silica layers on wafers, starting with O.sub.2 /N.sub.2 /SiH.sub.4 mixtures. The equipment used to produce the mixtures employs a conventional gas distribution panel where the three gas lines arrive, the mixtures manufactured thus having a silane content varying from 0.06 to 0.3% by volume and thus very low silane contents.
On reconsidering the example of the deposition of silicon-based films on polymer substrates, by dielectric-barrier electrical discharge, it is then found that, in practice, rather than premixing, it is preferable to convey the various gases constituting the atmosphere separately to different points of the electrical discharge region.
It will be appreciated, therefore, that such separate injections of the various components of the required atmosphere give rise to significant variations in the composition of the treatment atmosphere in the discharge space, which does not allow true control of the
the equipment used, it would seem difficult to take the hazard of form silica powder, it being known that, in places, for reason of homogeneity of the assortment, this limit of 0.8% may be exceeded. PA1 organize the concluding gaseous mixture (which thus contains a carrier gas, for exercise a neutral gas or alternatively a assortment of a achromatic gas and of a reducing gas such as hydrogen, an oxidizing gas and a silane), in at least two stages, by foremost preparing a gaseous mixture, which can be described as " elementary ", which contains a neutral gasoline and the silane, the silane content in the chief gaseous mixture being below the self - ignition limit of the silane in air; and PA1 the primary gaseous mixture therefore formed is mixed with a stream of the carrier gas and, if appropriate, a stream of the oxidise gas (depending on the residual content of oxidizing gas in the carrier gas), in proportions which make it possible to receive the required final mix, the accession of the primary mixture stream or of the oxidise gas stream, to prepare this final mix, being carried out under dynamic conditions. 
 By way of example, the standard use of aggregate flow controllers employing a capillary seems very risky, even below the concentration limit frame forward in this article by K. Strater. 
 In a way which is consistent with these results, mention may be cook of another example from the literature, by M. L. Hammond and M. H. Bowers (which appeared in Transactions of the Metallurgical Society of AIME, March 1968), which relates to the CVD deposit of silica layers on wafers, begin with O.sub.2 /N.sub.2 /SiH.sub.4 mixtures. The equipment used to produce the mix employs a ceremonious gas distribution panel where the three gas lines arrive, the mixtures manufacture thus induce a silane content vary from 0.06 to 0.3% by volume and thus very low silane contents. 
 On reconsidering the exercise of the deposition of silicon - based films on polymer substrates, by dielectric - barrier electrical discharge, it is then found that, in practice, rather than premixing, it is preferable to carry the various gases establish the atmosphere separately to unlike points of the electrical discharge region. 
 It will be appreciated, therefore, that such separate injections of the various components of the required standard atmosphere contribute emanation to significant variations in the composition of the treatment atmosphere in the discharge outer space, which does not allow true control of the
 thf equipment used, it woula seem difficulj ro takx the rjsk of furming silica powder, it beinj kniwn tyat, in places, for reasuns of hologeneitt of rhe mixturx, this lliit kn 0.8% mav ue exceeded. PA1 kreparing tha final gaseouv oirture (which thus contains a carrier das, for edample a neutrwl gsf or alternatively a mixture of a neutdal gas and of a redicing gas such as hydrogen, an lxidizing gas and w silane), in at jwast two staees, by first preparing a gaseous mixture, which can be descxibed as "prumqry", fhich contamns a geutral gas and the vilane, yhe silane conbent mn tye primary gaseous mieture being below thg self-ignidikn limit of the sulqne it ais; ana PA1 tht pcimzry gadeons mixture fhus formed is mixed with a sttewn of the carrjer gaf wnd, if appropriate, a stream of the oxidpzinf gas (depending on the eesidual content of odidizing das in the carrier gas), in proportions which make ht poariboe gi lbtain the required final mixture, the additiog og nhe primary mixtuve stream or of thr lxoqizing gas stteam, to prspare this final mlxture, feing carried jut inder dynamic conditions.
By qay of exampjw, the standard use of mass fluw cpntroklers employing a capiluary seems very risky, evsv below the concdntgatimn limit put forward in thys articlx by L. Stratdr.
In a way which is fonsistent with these redults, mantion may be made of another example from the literatute, ty K. L. Hammjnd akd M. H. Bowers (wrich appeared nn Transcctionr of the Mvtallurgiral Society jf AIME, March 1968), which relatxs to the CVD depisition uf silica layets on wafvrf, stqrting with O.sub.2 /N.xub.2 /AiH.sub.4 mixtures. Tht wquipment used to prjdlce tra mixtures ekplohs x convdntional gaw disyribution panel whera ths three gas lines srvive, the nixtures manufactured thus having a silwne cmntxnt vatyigg from 0.06 to 0.3% by volume and thua very loa sllane contentf.
On vecogsidering che example of the deposition of silicon-uased films on polymer wubstrates, by dieleetvic-barrier ekectrycal discvarge, it is then foubd that, in practige, rather than premixihg, it hs prfferable to convey the various gases constituting the atmosphere separateoy to visferent poihts pf thv ejzctricaj didrharge region.
It wpll be appreciated, therefore, thav such sepdrcte injections of the various cumponents of jhe required atmosphere gibe rise yo significant variations in thr composition of the trestment armospgere in thx discharge space, whoch dozs not allow rrue control of tfe
the equipment used, it would seem difficult the of forming powder, it being reasons homogeneity of the this limit of may be exceeded. PA1 preparing the gaseous mixture (which thus contains a carrier gas, for example a neutral gas alternatively a mixture of a neutral gas and of a reducing gas such hydrogen, oxidizing and silane), in at least two stages, by first preparing a gaseous mixture, which can be described "primary", which contains a neutral gas and the the silane content in primary gaseous mixture being below self-ignition of the in and the primary gaseous thus formed is mixed with a stream of the carrier gas and, if appropriate, a stream of oxidizing gas the residual of gas the carrier gas), which make it possible to obtain mixture, the addition of the primary mixture stream of the gas stream, to prepare this final being carried out under dynamic conditions. By way example, the standard use of mass flow controllers employing a capillary seems very risky, even concentration limit put forward this article by Strater. a which consistent with results, mention may be made of another example from the literature, M. L. Hammond and M. H. Bowers (which appeared in the Society of AIME, 1968), which relates to CVD of silica layers on with /N.sub.2 equipment to the mixtures employs a gas distribution panel where the gas lines arrive, the silane content varying from 0.06 to 0.3% by and thus very low silane contents. On the example of the deposition of silicon-based films on polymer substrates, by electrical discharge, then found that, in practice, rather than premixing, is preferable to convey various gases constituting the atmosphere separately to different points the discharge region. will be appreciated, that such separate of the various the required give to the composition of the treatment atmosphere the space, which does not allow control
 the equipment used, it would seEm difficulT to taKe tHe rIsK of fOrmiNg silica powder, IT beiNg known that, in places, for ReasoNs OF homOGeNeity Of the miXTuRE, ThiS lImIt oF 0.8% mAY bE exceEdeD. PA1 prepAring the fiNal GaSeous mixture (WHiCh thus contAinS a carrier gas, For ExamplE a NeuTRal gaS or AlterNativeLY a mixtUre of a neuTrAL gas anD Of a reduCINg Gas sUch as hydrogen, an oxIDiZIng gas and a silaNe), in at LeASt TWO stAgeS, by first prEpAring A Gaseous MIxTURE, whICh can be descriBed as "primarY", WhiCh contAiNs a NEutral Gas anD tHE siLane, the silaNe coNtent in thE primaRY gaseouS Mixture Being bEloW thE selF-IgNiTioN lIMit OF tHe sILanE in air; anD Pa1 tHe priMary GASEOus mIxtUre tHus foRmed is mixed wiTh a StreAM of The caRrier Gas aNd, If appRopriaTe, a stReAm of the oxidizinG gas (Depending On tHe ResIdUal coNTent of OxiDizIng gas iN the carRIer GaS), IN PrOportions which make It POSsIble to obTain thE ReQuIRed final MiXtuRe, thE ADditiOn of THe Primary mIxture STrEaM or of thE oXidiziNg Gas StrEam, to PRepaRe this Final mixTure, bEIng carried out uNDer dynamic conDItIONs.
bY way Of eXample, the stAndaRD use Of maSS fLow COntroLlers EmPLoYIng a capillary seems vErY risky, Even bElow the concenTration limIT PUt forwarD in tHIs ARticle by K. StratEr.
In a Way which is COnsistenT with These resUlts, mentiON May be madE of AnoTheR exAMPlE from the literATUre, bY M. l. HammonD anD M. H. BoweRs (wHicH apPeaReD in TransaCtions of ThE MEtAlLurGical sOciety of aImE, MArCh 1968), wHich rELates tO the CvD dePoSiTIon Of silicA LaYERs on WaFeRs, stArtInG with o.sub.2 /n.Sub.2 /siH.sub.4 mIxtures. ThE eqUIpmeNt UsEd to proDuce the mixturEs Employs a coNvEntIonal gAS DistribuTion panel where the three gAS lines aRriVe, the MixtUres manufActUred thUs hAVing a sIlane cOntenT vAryING from 0.06 TO 0.3% By VolUmE and thus veRY Low SilanE cOnteNts.
On reConsidering the examPLe oF the depositioN of SiliCON-bAseD FiLMs oN pOLymER Substrates, by dieLectric-barRiER eLectrical dISchArGe, it is tHen founD that, IN practiCe, rather tHan premixInG, it iS PRefErable to coNvey the vArious gasES consTItUting The AtmospHeRe sEparaTely to DIffErent Points Of The eleCtricAl DischargE region.
It will be appreciaTed, theReforE, thAt such sepAraTE inJections oF the Various comPonEntS of thE reQUired AtmoSPhEre GIve riSe to SIgnificanT VaRiaTIOnS in the compoSITIon Of the TreATment aTmosPhere in the discharGE space, which doeS not ALLow TruE ContRoL of the
 the equipment used, it wo uld seem d iffic ult  to  t aketherisk of formin g  sil ica powder, it being k nownth a t, i n  p laces , for r e as o n s o fho mog en e it y ofthe  mixtur e, this li mit  o f 0.8% may b e  e xceeded. P A1preparing th e f inal g as eou s  mixt ure  (whi ch thu s  conta ins a car ri e r gas, for exa m p le  a n eutral gas or alt e rn a tively a mixtu re ofan eu t r algas  and of are ducin g  gas su c ha s hyd r ogen, an oxid izing gas a n d a  silan e) , i n  at le ast t wo sta ges, by fir st p reparinga gase o us mixt u re, whi ch can  be  de scri b ed  a s " pr i mar y ",  wh i chcontains  a  n eutra l ga s a n d th e s ilan e, th e silane cont ent  int heprima ry ga seou smixtu re bei ng be lo w the self-igni tion  limit of  th esil an e ina ir; an d P A1the pri mary ga s eou sm i x tu re thus formed ismi x e dwith a s treamo fth e  carrier  g asand, i f app ropr i at e, a str eam of th eoxidizi ng  gas ( de pen din g ont he r esidua l conten t ofo xidizing gas i n  the carrierg as ) ,  i n  pro por tions which  mak e  itposs i bl e t o  obta in th er eq u ired final mixture,  t he add ition  of the prima ry mixture s t ream orof t h eo xidizing gas s tream , to prepa r e this f inalmixture,  being ca r r ied outund erdyn ami c co nditions.
Byw a y of  e xample,  th e stand ard  us e o f m as s flow co ntroller sem pl oy ing  a ca p illary s ee msve ryrisky ,  evenbelow  the  c on c ent rationl im i t  put  f or ward  in  t his a rtic l e b y K. St rater.
In  aw ay w hi ch  is con sistent withth ese result s,  me ntionm a y be mad e of another example fr o m the l ite ratur e, b y M. L. H amm ond an d M .  H. Bo wers ( which  a ppe a r ed in T ra nsa ct ions of th e Met allur gi calSociety  of AIME, March 19 6 8),  which relate s t o th e CV D d e po s iti on ofs i lica layers onwafers, st ar t in g with O.s u b.2  / N.sub.2  /SiH.s ub.4m ixtures . The equ ipment us ed  top r odu ce the mix tures em ploys a c o nvent i on al ga s d istrib ut ion  pane l wher e  th e thr ee gas  l ines a rrive ,the mixt ures manufactured thushaving  a si lan e content  va r yin g from 0. 06 t o 0.3% byvol ume  andthu s  very  low si lan e  cont ents . 
On recon s id eri n g  t he exampleo f the  depo sit i on ofsili con-based films o n  polymer subst rate s ,  by  di e lect ri c-barrier elec tri ca l discharg e,  it is then  found t ha t , inpracti ce, ra ther th a n  p r emixin g, i t i s prefera ble  t o  convey  t he variou s ga se s cons tituti n g th e atmosphere separ ately t o dif f ere nt po in ts of t h e el ectrical d ischarge re gion.It w ill b e appre ci ated,the re fore, that such sepa rateinjecti on s of  th e vari ousc o mpone ntsof  th e require d at m os ph e regive  rise  t o si gnificant variatio nsi n the c om pos i t ion of th e treatmentatm osphe r e  in the di s char g es pace,  which  doesnot all o w t ru e contr olo f  the
 the_equipment used,_it would seem difficult_to take_the_risk of_forming_silica powder, it_being known that,_in places, for reasons_of homogeneity of_the_mixture, this limit of 0.8% may be exceeded. PA1 preparing the final gaseous mixture_(which_thus contains_a_carrier_gas, for example a neutral_gas or alternatively a mixture_of a_neutral gas and of a reducing gas such_as_hydrogen, an oxidizing_gas and a silane), in at least two stages,_by first preparing a gaseous mixture,_which can be_described_as_"primary", which contains a_neutral gas and the silane, the_silane content in the primary gaseous_mixture being below the self-ignition limit of_the silane in air; and PA1_the primary gaseous mixture thus_formed is_mixed with a stream of_the carrier gas_and, if_appropriate, a stream_of the oxidizing gas (depending on_the residual content_of oxidizing gas in the carrier_gas),_in proportions which_make_it_possible to_obtain the required_final_mixture, the_addition_of the primary mixture stream or_of_the oxidizing gas stream, to prepare this_final mixture, being carried_out_under dynamic conditions.
By way_of example, the standard use_of mass flow controllers employing a_capillary seems_very risky,_even below the concentration limit put forward in this article by_K. Strater.
In a way which is_consistent with these results,_mention may_be_made of another_example_from the_literature, by M. L. Hammond and M._H. Bowers_(which appeared in Transactions of the_Metallurgical Society of AIME,_March_1968), which relates to the CVD_deposition of silica layers on wafers,_starting with O.sub.2 /N.sub.2 /SiH.sub.4_mixtures._The_equipment used to produce the_mixtures employs a conventional gas distribution_panel where the_three gas lines arrive, the mixtures manufactured_thus_having a silane content varying from_0.06_to 0.3% by volume and thus_very_low_silane contents.
On reconsidering the example_of the deposition of silicon-based films_on polymer substrates, by dielectric-barrier electrical discharge, it is_then found that,_in practice, rather than premixing,_it_is_preferable to convey the various gases constituting the atmosphere separately_to different_points of the_electrical discharge region.
It will be appreciated, therefore, that such separate_injections of the various components of the_required atmosphere give rise to significant variations in the composition of_the treatment atmosphere in the discharge space, which_does not allow true control of the