1. Isi usoro nke plasma emelitere kemịkalụ vepor ntinye
Plasma enhanced chemical vapor deposition (PECVD) bụ nkà na ụzụ ọhụrụ maka uto nke ihe nkiri dị gịrịgịrị site na mmeghachi omume kemịkalụ nke ihe ndị na-emepụta gas site n'enyemaka nke plasma na-egbuke egbuke. N'ihi na a na-akwado teknụzụ PECVD site na mwepu gas, a na-eji njirimara mmeghachi omume nke plasma na-adịghị nhata nke ọma, na mgbanwe usoro mmeghachi omume ume na-agbanwe agbanwe. N'ikwu okwu n'ozuzu, mgbe a na-eji teknụzụ PECVD akwadebe ihe nkiri ndị dị mkpa, uto nke ihe nkiri ndị dị mkpa gụnyere usoro atọ ndị a bụ isi.
Nke mbụ, na plasma na-abụghị nke nha, electrons na-emeghachi omume na gas mmeghachi omume na ọkwa mbụ iji mebie gas mmeghachi omume ma mepụta ngwakọta nke ion na ìgwè ndị na-arụ ọrụ;
Nke abuo, ụdị nile nke nọ n'ọrụ dị iche iche na-agbasa na ibuga n'elu na mgbidi nke ihe nkiri, na nke abụọ mmeghachi omume n'etiti reactants ime n'otu oge;
N'ikpeazụ, ụdị mmeghachi omume niile nke mbụ na nke abụọ na-eru n'elu uto na-adaba ma na-emeghachi omume na elu, na-esonyere ntọhapụ nke gaseous ụmụ irighiri ihe.
Kpọmkwem, teknụzụ PECVD dabere na usoro mwepu ọkụ nwere ike ime ka mmeghachi omume gas ionize mepụta plasma n'okpuru mkpali nke oghere electromagnetic mpụga. N'ime plasma na-egbuke egbuke, ike kinetic nke electrons accelerated site na eletrik eletrik dị n'èzí na-abụkarị ihe dị ka 10ev, ma ọ bụ karịa, nke zuru ezu iji bibie njikọ kemịkalụ nke ụmụ irighiri gas. Ya mere, site na nkukota na-adịghị ahụkebe nke electrons nwere ike dị elu na ikuku gas na-emeghachi omume, a ga-eme ka mkpụrụ ndụ gas ionized ma ọ bụ mebie iji mepụta atom na-anọpụ iche na ngwaahịa molekụla. A na-eme ka ion dị mma na-eme ngwa ngwa site na ion oyi akwa na-eme ngwa ngwa eletriki wee daa na electrode elu. Enwekwara obere ion oyi akwa eletrik dị nso na electrode dị ala, ya mere a na-agbanyekwa mkpụrụ ahụ site na ion ruo n'ókè ụfọdụ. N'ihi ya, ihe na-anọpụ iche na-emepụta site na ire ere na-agbasa na mgbidi tube na mkpụrụ. N'ime usoro mkpagharị na mgbasa, ihe ndị a na otu (a na-akpọ atom na-anọpụ iche nke kemịkalụ na ụmụ irighiri ihe) ga-enweta mmeghachi omume ion molecule na mmeghachi omume molecule otu n'ihi ụzọ dị mkpirikpi free. Ngwakọta kemịkalụ nke kemịkalụ kemịkalụ (karịsịa otu) nke na-erute mkpụrụ ma na-adsorbed na-arụ ọrụ nke ukwuu, a na-emepụta fim ahụ site na mmekọrịta dị n'etiti ha.
2. Mmeghachi omume kemịkalụ na plasma
N'ihi na mkpali nke mmeghachi omume gas na usoro mgbapụ ọkụ bụ tumadi nchikota elektrọn, mmeghachi omume elementrị na plasma dị iche iche, yana mmekọrịta dị n'etiti plasma na elu siri ike dịkwa mgbagwoju anya, nke na-eme ka o sie ike ịmụ usoro. Mgbanwe nke usoro PECVD. Ka ọ dị ugbu a, ọtụtụ usoro mmeghachi omume dị mkpa ka emeberela site na nnwale iji nweta ihe nkiri nwere ezigbo ihe. Maka ntinye nke ihe nkiri sịlịkọn dabere na teknụzụ PECVD, ọ bụrụ na usoro ntinye ego nwere ike ikpughe nke ukwuu, enwere ike ịbawanye ọnụọgụ nke ihe nkiri sịlịkọn dabere n'echiche nke ịgba mbọ hụ na akụrụngwa anụ ahụ dị mma.
Ka ọ dị ugbu a, n'ime nyocha nke ihe nkiri sịlịkọn, a na-eji hydrogen diluted silane (SiH4) eme ihe n'ọtụtụ ebe dị ka ikuku mmeghachi omume n'ihi na enwere ntakịrị hydrogen na ihe nkiri sịlịkọn. H na-arụ ọrụ dị oke mkpa n'ime ihe nkiri sịlịkọn nke dị mkpa. Ọ nwere ike jupụta dangling agbụ na ihe owuwu, ukwuu belata ntụpọ ike larịị, na mfe ịghọta valence eletrọnịkị akara nke ihe Ebe ọ bụ na ube et al. Buru ụzọ ghọta mmetụta doping nke ihe nkiri sịlịkọn dị gịrịgịrị wee kwadebe njikọ PN nke mbụ na, nyocha maka nkwadebe na ngwa nke ihe nkiri sịlịkọn dabere na teknụzụ PECVD ka emepụtara site na mli na oke. Ya mere, mmeghachi omume kemịkalụ na ihe nkiri sịlịkọn dabere na teknụzụ PECVD, ga-akọwa ma tụle ya n'ime ihe ndị a.
N'okpuru ọnọdụ mwepu na-egbuke egbuke, n'ihi na electrons na plasma silane nwere ihe karịrị ike EV, H2 na SiH4 ga-agbaze mgbe electrons na-ejikọta ha, nke bụ mmeghachi omume mbụ. Ọ bụrụ na anyị atụleghị steeti obi ụtọ dị n'etiti, anyị nwere ike nweta mmeghachi omume nkewa nke sihm (M = 0,1,2,3) na H.
e+SiH4→SiH2+H2+e (2.1)
e+SiH4→SiH3+H+e (2.2)
e+SiH4→Si+2H2+e (2.3)
e+SiH4→SiH+H2+H+e (2.4)
e+H2→2H+e (2.5)
Dị ka ọkọlọtọ okpomọkụ nke mmepụta nke ala ala ụmụ irighiri ihe, ike chọrọ maka n'elu dissociation usoro (2.1) ~ (2.5) bụ 2.1, 4.1, 4.4, 5.9 EV na 4.5 EV n'otu n'otu. Eletrọn ike dị elu na plasma nwekwara ike nweta mmeghachi omume ionization ndị a
e+SiH4→SiH2++H2+2e (2.6)
e+SiH4→SiH3++ H+2e (2.7)
e+SiH4→Si++2H2+2e (2.8)
e+SiH4→SiH++H2+H+2e (2.9)
Ike achọrọ maka (2.6) ~ (2.9) bụ 11.9, 12.3, 13.6 na 15.3 EV n'otu n'otu. N'ihi ọdịiche nke mmeghachi omume ike, ihe gbasara nke puru omume nke (2.1) ~ (2.9) mmeghachi omume bụ enweghị isi. Na mgbakwunye, sihm kpụrụ na usoro mmeghachi omume (2.1) ~ (2.5) ga-enweta mmeghachi omume nke abụọ na ionize, dị ka
SiH+e →SiH++2e (2.10)
SiH2+e →SiH2++2e (2.11)
SiH3+e →SiH3++2e (2.12)
Ọ bụrụ na mmeghachi omume a dị n'elu na-eme site na otu usoro eletrọn, ike achọrọ bụ ihe dịka 12 eV ma ọ bụ karịa. N'ihi na ọnụ ọgụgụ nke electrons dị elu karịa 10ev na plasma na-adịghị ike ionized na njupụta electron nke 1010cm-3 dị ntakịrị n'okpuru nrụgide ikuku (10-100pa) maka nkwadebe nke ihe nkiri ndị dabeere na silicon, The cumulative. Ihe puru omume nke ionization na-adịkarị obere karịa ike mkpali. Ya mere, ọnụ ọgụgụ nke ogige ionized dị n'elu na plasma silane dị ntakịrị, na otu sihm na-anọpụ iche na-achịkwa. Nsonaazụ nyocha nke oke dị iche iche gosikwara nkwubi okwu a [8]. Bourquard et al. Ọzọkwa rụtụrụ aka na ntinye nke sihm belatara n'usoro sih3, sih2, Si na SIH, mana ntinye nke SiH3 kacha karịa ugboro atọ nke SIH. Robertson et al. Kwuru na n'ime ngwaahịa na-anọpụ iche nke sihm, a na-ejikarị silane dị ọcha mee ihe maka nkwụsị ike dị elu, ebe a na-ejikarị sih3 mee ihe maka nkwụsịtụ dị ala. Usoro ntinye uche site na elu ruo ala bụ SiH3, SiH, Si, SiH2. Ya mere, usoro usoro plasma na-emetụta ike nke ngwaahịa sihm na-anọpụ iche.
Na mgbakwunye na nkewa ahụ dị n'elu na mmeghachi omume ionization, mmeghachi omume nke abụọ n'etiti ụmụ irighiri ionic dịkwa oke mkpa.
SiH2＋+SiH4→SiH3++SiH3 (2.13)
Ya mere, n'ihe gbasara ntinye ion, sih3 + karịrị sih2 +. Ọ nwere ike ịkọwa ihe kpatara enwere sih3 + ion karịa sih2 + ion na plasma SiH4.
Na mgbakwunye, a ga-enwe mmeghachi omume nkukota nke atom nke hydrogen na plasma na-ejide hydrogen na SiH4.
H+ SiH4→SiH3+H2 (2.14)
Ọ bụ mmeghachi omume exothermic na ihe mmalite maka nhazi nke si2h6. N'ezie, ìgwè ndị a abụghị nanị na ala ala, ma na-enwekwa obi ụtọ na ọnọdụ obi ụtọ na plasma. Ntugharị ikuku nke plasma silane na-egosi na enwere mgbanwe mgbanwe anya nke ọma nke Si, SIH, h, na steeti obi ụtọ nke SiH2, SiH3.
Oge nzipu: Eprel-07-2021