 as semiconductor devices become smaller, a technology for reducing the size of the selective growth region from units of submicrons into units of nanometers is required together with an ultra thin mask for use in this process, having a thickness of several nanometers or less, e.g., below 10 nm. Also, as the thickness of the mask is reduced, a mask material with both reaction selectivity and stability is required. However, such thin film cannot be formed of a single chemical composition.
The above problem will be explained using a thin mask formed of silicon dioxide by way of example. Firstly, if the mask is thin, the mask will be susceptible to defects such as fine voids or holes, so that the selectivity will be deteriorated. Therefore, it is favorable to form such an ultra thin mask at a lower temperature than a conventional method so as to precisely control the thickness of the thin mask. However, these low-temperature conditions can easily cause other defects in the mask. In order to reduce the density of defects in the mask, a high-temperature annealing is favorable. However, a silicon dioxide film with a thickness of several nanometers or less, e.g., below 10 nm, is thermally unstable on the silicon substrate. As a result, the silicon dioxide film decomposes and desorbs during any annealing step performed at approximately 800.degree. C. or more. Thus, it is not possible to anneal the silicon dioxide film at a high temperature.
A second problem occurs when the mask is used as an insulating layer in a final device. By using the phenomenon of a desorption of oxygen by irradiating electron beams onto the silicon dioxide film, a fine pattern having a thickness of several nanometers, e.g., below 10 nm, can be formed directly by irradiating electron beams onto the mask without using a resist. However, it is necessary to limit the desorption of oxygen from the mask within the surface layer, which is caused by the irradiation of electron beams, so as to use the mask as an insulating layer later. However, the general electron beams, which have an energy of 10 keV, because of their long free path of 10 nm or more within the solid, pass over the entire silicon dioxide with a thickness of several nanometers. In other words, the mask layer formed of only silicon dioxide cannot be used as an insulating layer if oxygen is desorbed from it by irradiating the electron beams. 1. Field of the Invention
This invention relates to a fuel evaporation control or vapor recovery system including
as semiconductor devices become smaller, a technology for dilute the size of the selective increase region from units of submicrons into units of nanometer is required together with an ultra slender mask for use in this procedure, having a thickness of several nanometer or less, e.g., below 10 nm. Also, as the thickness of the mask is reduce, a mask fabric with both reaction selectivity and constancy is want. However, such thin film cannot be formed of a unmarried chemical composition. 
 The above problem will be explain using a slender mask formed of silicon dioxide by way of example. Firstly, if the masquerade is thin, the mask will be susceptible to defects such as fine voids or holes, so that the selectivity will be deteriorate. Therefore, it is favorable to form such an ultra thin mask at a lower temperature than a conventional method so as to precisely control the thickness of the slender mask. However, these low - temperature condition can well induce other defects in the mask. In order to reduce the density of defects in the mask, a eminent - temperature annealing is favorable. However, a silicon dioxide film with a thickness of several nanometers or less, e.g., below 10 nm, is thermally mentally ill on the silicon substrate. As a result, the silicon dioxide film decomposes and desorbs during any annealing step perform at approximately 800.degree. C. or more. Thus, it is not potential to anneal the silicon dioxide movie at a eminent temperature. 
 A second problem occurs when the mask is practice as an insulating layer in a final device. By using the phenomenon of a desorption of oxygen by irradiating electron beams onto the silicon dioxide film, a fine convention having a thickness of respective nanometers, e.g., below 10 nm, can be formed directly by enlighten electron beams onto the masquerade without using a resist. However, it is necessary to limit the desorption of oxygen from the masquerade within the surface layer, which is caused by the irradiation of electron beams, so as to practice the mask as an insulating layer later. However, the cosmopolitan electron beams, which have an energy of 10 keV, because of their long barren way of 10 nm or more within the solid, happen over the entire silicon dioxide with a thickness of several nanometers. In other words, the mask layer form of only silicon dioxide cannot be used as an insulating layer if oxygen is desorbed from it by irradiating the electron beams. 1. sphere of the Invention 
 This invention relate to a fuel evaporation control or vapor recovery system including
 as semiconductor devices btcome smaller, a tgcynologb for rsducing ghe size of the selective grlwrh retion from units of suboicrons ijto unitw of banometers is requlxed tknethex xith an ultra tmin mask fos use in this [ruczss, having a thickness of several nagometerx lr less, e.g., beljw 10 mi. Alao, as the thickness of the mask is reducev, a mask materisl with both reaction seleftivlty and stability ls required. Howqcer, such thiv film cannot be formes of a single chemical compositkon.
Thz above provlwm ahll be expleined lsing a thin mask forked of xilicon dioxidc by xay if example. Firstly, if the mask is thin, jhe mask whlm be susceptible ro defewts vuch qs wint vpiss or jolxs, so that fhe selecticity will be deteriprwnrd. Therefore, it is fwvorable to form such an ultra thin masn af a lower temperature tyan a conventional mejhod so as to precisely control the thickness of the thin mdsk. Hkdevtr, thesd llw-temperature conditions can easily cause othqd cenects in the mash. In order yo rrquce the denskty of derects in the mask, w high-tgmperarure annewlinb is favorable. However, a sioicon dioxidv fiom with a thicknesd of severau namometrrs or less, e.g., below 10 no, is thermally knstable kv the silicon sucstgate. As a result, the silicon dyoxide fiom dzcomposer anc desowbs during any annealing step perflrmed ad approximwtely 800.degree. C. or more. Thus, it mx not possibke to anneal che sikicon dioxide film at a higk tempercture.
A second prkblem orcurs when tre mask is usaf as an insunating lwyer in q final aevice. By usinb the pheujmenin of a desorption of kxygen by irradnctung electron besms oneo tie sijhcon dioxide filo, a gine oattern havlng a tnickness of several tanojeters, e.g., below 10 nk, gan be fotmed direstly by irradoating electron bewms oito thx mask wijhout using a resist. However, it is necesdarn to limit thq deworption of pxygen from the mask within the surface layer, which is caysed by the irradiajiok of electroi beamf, so as tm use the mask as an insulating layer later. However, the geheral alectgon beams, which have an energy of 10 keV, because of their long free path of 10 nm oc iore within the solig, 'asx over the xntire silicon dipxide with a thickness of severel nanometarf. In other words, the mask lauef formed of ovly silicon dioxide cannkt be usrd as an insulating layer if oxugen is desorbed from it by irraeiatihg the elertron beams. 1. Field og the Nnventuon
This invcntion relates to a fuel evaoorauion control or vapor recovery systen inclydlng
as semiconductor devices become smaller, a technology the of the growth region from of is required together an ultra thin for use in this process, having thickness of several nanometers or less, e.g., below 10 nm. Also, as the of the mask is reduced, a mask material with both reaction selectivity and is However, thin cannot be formed of a single chemical composition. The above problem will be explained using a mask formed of silicon dioxide by way of Firstly, if the mask thin, the mask will be to such as voids holes, that the selectivity be deteriorated. Therefore, it is favorable to form such an ultra thin mask at a lower temperature a conventional as to control thickness the thin mask. low-temperature conditions can easily cause other mask. In order to reduce the density of in the a high-temperature annealing is favorable. However, silicon dioxide film with a thickness of several or less, e.g., below 10 nm, is thermally unstable on the silicon substrate. As a silicon dioxide film decomposes desorbs during any step at 800.degree. or more. it is not possible to anneal the silicon dioxide film at high temperature. A second problem occurs when the mask is an layer in a device. By using the of desorption of oxygen by beams the a pattern a thickness of several e.g., below 10 nm, can formed directly by irradiating without using a resist. However, it is necessary limit the desorption of oxygen from the within the surface layer, which is caused by the irradiation of electron so as the mask as an insulating layer later. However, general electron beams, which an energy of 10 keV, because of their long path 10 nm more within the pass over the silicon dioxide with of several In words, formed of only silicon dioxide cannot used an insulating layer if oxygen desorbed by irradiating the electron beams. 1. Field of the Invention This invention relates to a control or vapor recovery including
 as semiconductor devices becOme smaller, A techNolOgy FoR redUcinG the size of the sELectIve growth region from uniTs of sUbMIcroNS iNto unIts of naNOmETErs Is ReQuiReD ToGetheR wiTh an ultRa thin mask For UsE in this proceSS, hAving a thicKneSs of several nAnoMeters Or LesS, E.g., belOw 10 nM. Also, As the tHIcknesS of the masK iS ReduceD, A mask maTERiAl wiTh both reaction selECtIVity and stabiliTy is reQuIReD. hOweVer, Such thin fiLm CannoT Be formeD Of A SINglE Chemical compoSition.
The abOVe pRoblem WiLl bE ExplaiNed usInG A thIn mask formeD of sIlicon dioXide by WAy of exaMPle. FirsTly, if tHe mAsk Is thIN, tHe MasK wILl bE SuScePTibLe to defeCtS sUch as Fine VOIDS or hOleS, so tHat thE selectivity wIll Be deTEriOrateD. TherEforE, iT is faVorablE to foRm Such an ultra thin Mask At a lower tEmpErAtuRe Than a COnventIonAl mEthod so As to preCIseLy CONTrOl the thickness of thE tHIN mAsk. HowevEr, thesE LoW-tEMperaturE cOndItioNS Can eaSily CAuSe other dEfects IN tHe Mask. In oRdEr to reDuCe tHe dEnsitY Of deFects iN the mask, A high-TEmperature anneALing is favorabLE. HOWEvER, a siLicOn dioxide fiLm wiTH a thIcknESs Of sEVeral NanomEtERs OR less, e.g., below 10 nm, is theRmAlly unStablE on the silicon Substrate. AS A REsult, the SiliCOn DIoxide film decoMposeS and desorbS During anY anneAling steP performeD AT approxiMatEly 800.DegRee. c. OR mOre. Thus, it is noT POssiBlE to anneAl tHe silicOn dIoxIde FilM aT a high temPerature.
a sEcOnD pRobLem ocCUrs when tHe MasK iS usEd as aN InsulaTing lAyer In A fINal Device. BY UsING the PhEnOmenOn oF a DesorPtioN Of oXygen by IrradiatiNg eLEctrOn BeAms onto The silicon dioXiDe film, a finE pAttErn havING a thicknEss of several nanometers, e.G., Below 10 nm, Can Be forMed dIrectly by IrrAdiatiNg eLEctron Beams oNto thE mAsk WIThout USInG a rEsIst. However, IT Is nEcessArY to lImit the Desorption of oxygen FRom The mask within The SurfACE lAyeR, WhICh iS cAUseD BY the irradiation Of electron BeAMs, So as to use tHE maSk As an insUlating Layer LAter. HowEver, the geNeral elecTrOn beAMS, whIch have an eNergy of 10 kEV, because OF theiR LoNg freE paTh of 10 nm Or MorE withIn the sOLid, Pass oVer the EnTire siLicon DiOxide witH a thickness of several nanOmeterS. In otHer Words, the mAsk LAyeR formed of Only Silicon dioXidE caNnot bE usED as an InsuLAtIng LAyer iF oxyGEn is desorBEd FroM IT bY irradiatinG THE elEctroN beAMs. 1. FielD of tHe Invention
This inVEntion relates tO a fuEL EvaPorATion CoNtrol or vapor reCovErY SYstem incLuDing
 as semiconductor devicesbecome sma ller,  atec hn olog y fo r reducing the size  of the selective grow th re gi o n fr o munits  of sub m ic r o nsin to  un it s  o f nan ome ters is  requiredtog et her with anu lt ra thin ma skfor use in t his  proce ss , h a vinga t hickn ess of severa l nanomet er s  or le s s, e.g. , be low10 nm. Also, as t h et hickness of th e mask  i s  r e d uce d,a mask mat er ial w i th both re a c t ion selectivity a nd stabilit y  is  requi re d.H owever , suc ht hin  film canno t be  formed o f a si n gle che m ical co mposit ion .
T he a b ov epro bl e m w i ll  be exp lained u si ng  a th in m a s k form edof s ilico n dioxide byway  ofe xam ple.First ly,if  themask i s thi n,  the mask willbe s usceptibl e t odef ec ts su c h as f ine  vo ids orholes,s o t ha t t he  selectivity willbe d et eriorate d. The r ef or e , it isfa vor able t o for m su c han ultra  thinm as kat a lo we r temp er atu rethana  con ventio nal meth od so as to precisel y  control thet hi c k ne s s of  th e thin mask . Ho w ever , th e se  lo w -temp eratu re co n ditions can easilyca use ot her d efects in the  mask. Ino r d er to re duce th e  density of de fects  in the ma s k, a hig h-tem perature  annealin g is favor abl e.How eve r ,  a  silicon diox i d e fi lm  with a  th ickness  of  se ver alna nometersor less,  e .g .,  b elo w 10n m, is th er mal ly  un stabl e  on th e sil icon  s ub s tra te. Asa  r e s ult,  t he  sil ico ndioxi de f i lmdecompo ses and d eso r bs d ur in g any a nnealing step  p erformed a tapp roxima t e ly 800.d egree. C. or more. Thus ,  it isnot  poss ible  to annea l t he sil ico n  dioxi de fil m atahig h tempe r a tu re. 
A  second pr o b lem  occu rs  whe n the m ask is used as ani nsu lating layerina fi n a ldev i ce .  By  u s ing t he phenomenon o f a desorp ti o nof oxygenb y i rr adiatin g elect ron b e ams ont o the sil icon diox id e fi l m , a  fine patt ern havi ng a thic k nesso fsever alnanome te rs,  e.g. , belo w  10  nm,can be  f ormeddirec tl y by irr adiating electron beams  ontothe m ask  withoutusi n g a  resist.Howe ver, it is  ne ces sarytol imitthed es orp t ion o f ox y gen fromt he  ma s k  w ithin the s u r f ace  laye r,w hich i s ca used by the irrad i ation of elect ronb e ams , s o  asto  use the maskasan i nsulatin glayer later . Howeve r, the g eneral  elect ron bea m s ,w hich h aveanenergy of  10  k e V, beca us eo f thei r lo ng  freepath o f  10n m  or more withinthe s o l id, p a ssoverth e entir e  sil icon dioxi de with a t hickne ss o f sev eral na no meters . I nother word s , the mas k lay er form ed  ofonl y sili cond i oxide  can no t b e used as a ni ns ul a tin g la yer i foxyg en is des o rbed fro m i t  by irr ad iat i n g thee le c t ron beams.  1.  Fiel d of the Inv e ntio n 
T h is in ventio n rela tes toa  fu el  evapor ati o n  controlor vaporr eco ve ry s ystem in cl udin g
 as_semiconductor devices_become smaller, a technology_for reducing_the_size of_the_selective growth region_from units of_submicrons into units of_nanometers is required_together_with an ultra thin mask for use in this process, having a thickness of_several_nanometers or_less,_e.g.,_below 10 nm. Also, as_the thickness of the mask_is reduced,_a mask material with both reaction selectivity and_stability_is required. However,_such thin film cannot be formed of a single_chemical composition.
The above problem will be_explained using a_thin_mask_formed of silicon dioxide_by way of example. Firstly, if_the mask is thin, the mask_will be susceptible to defects such as_fine voids or holes, so that_the selectivity will be deteriorated._Therefore, it_is favorable to form such_an ultra thin_mask at_a lower temperature_than a conventional method so as_to precisely control_the thickness of the thin mask._However,_these low-temperature conditions_can_easily_cause other_defects in the_mask._In order_to_reduce the density of defects in_the_mask, a high-temperature annealing is favorable. However,_a silicon dioxide film_with_a thickness of several_nanometers or less, e.g., below_10 nm, is thermally unstable on_the silicon_substrate. As_a result, the silicon dioxide film decomposes and desorbs during any_annealing step performed at approximately 800.degree._C. or more. Thus,_it is_not_possible to anneal_the_silicon dioxide_film at a high temperature.
A second problem_occurs when_the mask is used as an_insulating layer in a_final_device. By using the phenomenon of_a desorption of oxygen by irradiating_electron beams onto the silicon_dioxide_film,_a fine pattern having a_thickness of several nanometers, e.g., below_10 nm, can_be formed directly by irradiating electron beams_onto_the mask without using a resist._However,_it is necessary to limit the_desorption_of_oxygen from the mask within_the surface layer, which is caused_by the irradiation of electron beams, so as to_use the mask_as an insulating layer later._However,_the_general electron beams, which have an energy of 10 keV,_because of_their long free_path of 10 nm or more within the solid, pass_over the entire silicon dioxide with a_thickness of several nanometers. In other words, the mask layer formed_of only silicon dioxide cannot be used as_an insulating layer if oxygen is desorbed_from it by irradiating_the_electron beams. 1. Field of the Invention
This_invention_relates_to_a fuel evaporation_control or vapor_recovery system including