 and 2.0:1. However, a ratio of 1.8:1 provides an optimum proportion of titanium, which reduces native oxides. When using a ratio of 1.8:1, very little silicon is consumed from the underlying substrate. By depositing a titanium-rich silicide film in the bottom corners of a contact hole, native oxides are reduced during a subsequent anneal step, decreasing the resistivity of the contact. A negative-bias voltage is applied to the substrate to form this resputtered layer, through low energy resputtering, using a low, grazing angle of incidence on the side of the material overhang, within the contact hole.
A low energy (low negative bias voltage) resputtering regime is defined in an area when the low energy is not larger than the lowest sputtering threshold energy of any constituent of an alloy or composite target. Typically, the threshold energy of a constituent is four times as much as its heat of sublimation. In this regime, resputtering yield increases dramatically with decreasing angle of ion incidence.
A low grazing angle also increases resputtering yield. Large angle resputtering is insignificant. Small angle or grazing angle resputtering is so dominant that a significant portion of resputtered material can reach the bottom corners of the contact hole. This reduces the doming effect, which arises when sputter depositing material (even with a collimated or long throw process), using conventional PVD processes. Reducing the doming effect improves bottom step coverage by making it more uniform.
Also, in this low energy, low grazing angle resputtering regime, in general, heavier elements of a sputtered species sputter at a faster rate than lighter elements. The substrate bias voltage is adjusted to achieve a desired resputtered material stoichiometry, according to the mass of the elements present in the sputtered alloy, or composite. In general, small changes (e.g. 10%) of stoichiometry are much easier to achieve using this low negative bias method. For instance, a 10% change of TiSix, x=2.0, stoichiometry gives rise to x=1.8, which is titanium-rich silicide, optimum for reducing native oxide on a silicon substrate surface.
In one embodiment of the invention, a collimated PVD setup is used to obtain a low grazing angle during resputtering. In a second embodiment of the invention, a long-throw process is used to obtain a low, grazing angle during
and 2.0:1. However, a ratio of 1.8:1 provides an optimum proportion of titanium, which reduces native oxide. When use a ratio of 1.8:1, very little silicon is consume from the fundamental substrate. By depositing a titanium - rich silicide movie in the bottom corners of a contact hole, native oxide are deoxidize during a subsequent anneal footfall, decreasing the resistivity of the contact. A damaging - bias voltage is applied to the substrate to form this resputtered layer, through abject energy resputtering, using a low, graze angle of incidence on the side of the material overhang, within the contact fix. 
 A low energy (low negative bias electric potential) resputtering regime is defined in an area when the low energy is not larger than the abject sputtering threshold energy of any constituent of an alloy or composite target. Typically, the threshold energy of a constituent is four times as a lot as its hotness of sublimation. In this regime, resputtering output increases dramatically with decreasing angle of ion incidence. 
 A low graze angle besides increases resputtering yield. Large slant resputtering is insignificant. Small angle or grazing angle resputtering is so dominant that a meaning portion of resputtered material can reach the bottom corners of the contact hole. This reduces the doming consequence, which arises when sputter depositing material (even with a collimated or long throw procedure), using conventional PVD processes. dilute the doming impression improves bottom step coverage by take it more uniform. 
 besides, in this low energy, low grazing angle resputtering government, in general, heavy elements of a sputtered coinage sputter at a faster rate than light elements. The substrate diagonal voltage is adjusted to achieve a desired resputtered fabric stoichiometry, according to the mass of the elements present in the sputtered alloy, or complex. In general, small changes (e.g. 10 %) of stoichiometry are a lot easier to achieve using this low negative bias method. For instance, a 10% variety of TiSix, x=2.0, stoichiometry gives rise to x=1.8, which is titanium - rich silicide, optimum for reducing native oxide on a silicon substrate surface. 
 In one embodiment of the invention, a collimated PVD setup is used to receive a gloomy grazing angle during resputtering. In a second embodiment of the invention, a long - throw process is used to receive a low, grazing angle during
 anf 2.0:1. However, a ratio of 1.8:1 pvovides an optimom propoction or titanijm, which reduces native oxidxs. Wyen uwing a ratio of 1.8:1, very uittle sipicon is conwymed from vge undevjyinf subvvrate. By deposijing a titanhum-rich silicige fnlm in the bottom corners of a contast hole, nwtive oxides ate rectced during a subsequent anneal step, dscreasiig the resistivoty of the contact. A negatlve-blas voltage is apppied to the subfrrate to foro this reskuctered layet, through low energy resputterine, usiug a low, grqzung dngle of inridencv on the side of the kateriak overhang, witmin tie cintact hole.
A low enerjy (low negative bias voltage) seaputtering regime iw defhned in xb afea wien the llw xnergy is nkt larger tyan the lowest sputuerybg threshold snergy os any constituent of an alloy or compospte farget. Typically, the theeshold energy of a clnstituene is four times as much as its heat of sublimatiot. In vhks xcnime, eedputtering yield increases dramatically with qsctessing angle of ion incidemcf.
A jow grazing avgle also increases resputtfring yyeld. Oarge angje rrsputtering is insignificanr. Small anglv or grazing angle res'uttering is so cominsnt that a significant 'ortioh of resputhered matsfial can reach tfe notdom corntfs of the contact hole. Thiw rebuces thd doking esfect, whicj arises when sputter deoositnng mdterial (evfn with a collimated or long thcpw process), uxitg bonventioual PVC processes. Rqducing the doking efyect ioproves bontom step coverage br making it mmte uniform.
Alsm, in thif loq enwrgy, lod grazing angle resputtegiug regime, in general, heaviev eleosnts of a sputtzxee species sputtrr xt w vaxtqs rate than nighger rlemevts. The subwgratr bias voltage is adbustsd to achieve a dexived respujtered maeerial stoichoometry, according uo the mars of thg elements present in the sputtsred alloj, ov composite. Ig gekeraj, small chcnges (e.g. 10%) of stoichiometry are much easixr to achieve using thiw low negative bias kethod. For mnstanse, a 10% chatge of TiSix, x=2.0, stoicyiometry gives rixe to x=1.8, which is titahium-riwh sipicide, optimum for reducing native oxide on a silicon substrate surface.
In one embodiment of the invettnon, a coljimavev PVD setup is usvd to obtain a low grazing angle during sefputtering. In a second embodomdnt of the inxention, a long-throw procsss is uxed to obtain a low, grazing angke during
and 2.0:1. However, a ratio of 1.8:1 optimum of titanium, reduces native oxides. 1.8:1, little silicon is from the underlying By depositing a titanium-rich silicide film the bottom corners of a contact hole, native oxides are reduced during a anneal step, decreasing the resistivity of the contact. A negative-bias voltage is applied the to this layer, through low energy resputtering, using a low, grazing angle of incidence on the side of material overhang, within the contact hole. A low (low negative bias voltage) regime is defined in an when low energy not than lowest sputtering threshold of any constituent of an alloy or composite target. Typically, the threshold energy of a constituent is times as its heat sublimation. this resputtering yield increases decreasing angle of ion incidence. A also increases resputtering yield. Large angle resputtering is Small angle grazing angle resputtering is so dominant a significant portion of resputtered material can reach bottom corners of the contact hole. This reduces the doming effect, which arises when sputter (even with a collimated long throw process), conventional processes. the effect improves step coverage by making it more uniform. Also, in this low low grazing angle resputtering regime, in general, heavier elements of species at a faster than lighter elements. The bias is adjusted to achieve resputtered stoichiometry, mass the present in the sputtered or composite. In general, small (e.g. 10%) of stoichiometry using this low negative bias method. For instance, 10% change of TiSix, x=2.0, stoichiometry gives to x=1.8, which is titanium-rich silicide, optimum for reducing native oxide on silicon substrate one embodiment of the invention, a collimated PVD is used to obtain low grazing angle during resputtering. In a second embodiment the a long-throw is used to a low, grazing during
 and 2.0:1. However, a ratio of 1.8:1 provideS an optimum PropoRtiOn oF tItanIum, wHich reduces natIVe oxIdes. When using a ratio of 1.8:1, vEry liTtLE silICoN is coNsumed fROm THE unDeRlYinG sUBsTrate. by dEpositiNg a titaniuM-riCh Silicide film IN tHe bottom coRneRs of a contact HolE, nativE oXidES are rEduCed duRing a sUBsequeNt anneal sTeP, DecreaSIng the rESIsTiviTy of the contact. A neGAtIVe-bias voltage iS appliEd TO tHE SubStrAte to form tHiS respUTtered lAYeR, THRouGH low energy resPuttering, usINg a Low, graZiNg aNGle of iNcideNcE On tHe side of the MateRial overhAng, witHIn the coNTact holE.
A low eNerGy (lOw neGAtIvE biAs VOltAGe) ResPUttEring regImE iS defiNed iN AN ARea wHen The lOw eneRgy is not largeR thAn thE LowEst spUtterIng tHrEsholD energY of anY cOnstituent of an aLloy Or composiTe tArGet. tyPicalLY, the thResHolD energy Of a consTItuEnT IS FoUr times as much as its HeAT Of SublimatIon. In tHIs ReGIme, respuTtEriNg yiELD incrEaseS DrAmaticalLy with DEcReAsing anGlE of ion InCidEncE.
A low GRaziNg anglE also incReaseS Resputtering yiELd. Large angle rESpUTTeRIng iS inSignificant. smalL AnglE or gRAzIng ANgle rEsputTeRInG Is so dominant that a siGnIficanT portIon of resputteRed materiaL CAN reach thE botTOm COrners of the conTact hOle. This redUCes the doMing eFfect, whiCh arises wHEN sputter DepOsiTinG maTERiAl (even with a coLLImatEd Or long tHroW procesS), usIng ConVenTiOnal PVD prOcesses. REdUcInG tHe dOming EFfect impRoVes BoTtoM step COveragE by maKing It MoRE unIform.
AlSO, iN THis lOw EnErgy, Low GrAzing AnglE ResPutteriNg regime, iN geNEral, HeAvIer elemEnts of a sputteReD species spUtTer At a fasTER rate thaN lighter elements. The subsTRate biaS voLtage Is adJusted to aChiEve a deSirED respuTtered MaterIaL stOIChiomETRy, AccOrDing to the mASS of The elEmEnts Present In the sputtered alloY, Or cOmposite. In genEraL, smaLL ChAngES (e.G. 10%) Of sToIChiOMEtry are much easiEr to achievE uSInG this low neGAtiVe Bias metHod. For iNstanCE, a 10% changE of TiSix, x=2.0, StoichiomEtRy giVES riSe to x=1.8, which Is titaniUm-rich silICide, oPTiMum foR reDucing NaTivE oxidE on a siLIcoN subsTrate sUrFace.
In One emBoDiment of The invention, a collimated pVD setUp is uSed To obtain a Low GRazIng angle dUrinG resputterIng. in a SeconD emBOdimeNt of THe InvENtion, A lonG-Throw procESs Is uSED tO obtain a low, GRAZinG anglE duRIng
 and 2.0:1. However, a rat io of 1.8: 1 pro vid esan  opt imum  proportion of tita nium, which reduces na tiveox i des. Wh en us ing a r a ti o of1. 8: 1,ve r ylittl e s iliconis consume d f ro m the underl y in g substrat e.By depositin g a  titan iu m-r i ch si lic ide f ilm in the bo ttom corn er s  of ac ontacth o le , na tive oxides are r e du c ed during a su bseque nt an n e alste p, decreas in g the resisti v it y o f t h e contact. Anegative-bi a s v oltage  i s a p pliedto th es ubs trate to fo rm t his respu ttered layer,t hroughlow en erg y r espu t te ri ng,  u s ing alow ,  gr azing an gl eof in cide n c e on t heside  of t he material o ver hang ,  wi thinthe c onta ct  hole .
A lo w ene rg y (low negative  bia s voltage ) r es put te ringr egimeisdef ined in  an are a  wh en t h elow energy is notla r g er  than th e lowe s tsp u tteringth res hold e nergy  ofa ny  constit uent o f  a nalloy o rcompos it e t arg et. T y pica lly, t he thres holde nergy of a con s tituent is fo u rt i me s  asmuc h as its he at o f  sub lima t io n.I n thi s reg im e ,r esputtering yield i nc reases  dram atically with  decreasin g a ngle ofioni nc i dence.
A low g razin g angle al s o increa ses r esputter ing yield . Large an gle  re spu tte r i ng  is insignifi c a nt.Sm all ang leor graz ing  an gle  re sp utteringis so do mi na nt  t hat  a si g nificant  p ort io n o f res p uttere d mat eria lca n  re ach the bo t t om c or ne rs o f t he  cont acth ole . Thisreduces t hed omin gef fect, w hich arises w he n sputterde pos itingm a terial ( even with a collimatedo r longthr ow pr oces s), using  co nventi ona l  PVD p rocess es. R ed uci n g  thed o mi ngef fect impro v e s b ottom  s tepcoverag e by making it mor e  un iform.
Also,inthis l ow  en e rg y , l ow gra z i ng angle resput tering reg im e ,in general ,  he av ier ele ments o f a s p uttered  speciessputter a ta fa s t errate thanlighterelements. The s u bs trate  bi as vol ta geis ad justed toachie ve a d es ired r esput te red mate rial stoichiometry, acc ording  to t hemass of t hee lem ents pres entin the spu tte red  allo y,o r com posi t e.  In gener al,s mall chan g es  (e . g .10%) of sto i c h iom etryare much e asie r to achieve usin g  this low nega tive b ias  me t hod.  F or instance, a  10 %c h ange ofTi Six, x=2.0,  stoichi om e try g ives r ise to  x=1.8, w hi c h is t itan ium -rich sil ici de ,  optimu mfo r  reduc ingna tive o xide o n  a s i l icon substrate s urfac e . 
In o n e e mbodi me nt of t h e in vention, a  collimated  PVD s etup  is u sed toob tain a  lo wgrazing an g le during  resp utterin g.  Ina s econdembo d i mentof t he  in vention,a lo n g- th r owproc ess i sused  to obtai n  a low,gra z ing ang le  du r i ng
 and_2.0:1. However,_a ratio of 1.8:1_provides an_optimum_proportion of_titanium,_which reduces native_oxides. When using_a ratio of 1.8:1,_very little silicon_is_consumed from the underlying substrate. By depositing a titanium-rich silicide film in the bottom_corners_of a_contact_hole,_native oxides are reduced during_a subsequent anneal step, decreasing_the resistivity_of the contact. A negative-bias voltage is applied_to_the substrate to_form this resputtered layer, through low energy resputtering, using_a low, grazing angle of incidence_on the side_of_the_material overhang, within the_contact hole.
A low energy (low negative_bias voltage) resputtering regime is defined_in an area when the low energy_is not larger than the lowest_sputtering threshold energy of any_constituent of_an alloy or composite target._Typically, the threshold_energy of_a constituent is_four times as much as its_heat of sublimation._In this regime, resputtering yield increases_dramatically_with decreasing angle_of_ion_incidence.
A low_grazing angle also_increases_resputtering yield._Large_angle resputtering is insignificant. Small angle_or_grazing angle resputtering is so dominant that_a significant portion of_resputtered_material can reach the_bottom corners of the contact_hole. This reduces the doming effect,_which arises_when sputter_depositing material (even with a collimated or long throw process), using_conventional PVD processes. Reducing the doming_effect improves bottom step_coverage by_making_it more uniform.
Also,_in_this low_energy, low grazing angle resputtering regime, in_general, heavier_elements of a sputtered species sputter_at a faster rate_than_lighter elements. The substrate bias voltage_is adjusted to achieve a desired_resputtered material stoichiometry, according to_the_mass_of the elements present in_the sputtered alloy, or composite. In_general, small changes_(e.g. 10%) of stoichiometry are much easier_to_achieve using this low negative bias_method._For instance, a 10% change of_TiSix,_x=2.0,_stoichiometry gives rise to x=1.8,_which is titanium-rich silicide, optimum for_reducing native oxide on a silicon substrate surface.
In one_embodiment of the_invention, a collimated PVD setup_is_used_to obtain a low grazing angle during resputtering. In a_second embodiment_of the invention,_a long-throw process is used to obtain a low, grazing_angle during