US6180420B1
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Low temperature CVD processes for preparing ferroelectric films using Bi carboxylates
Assignee: Qimonda AG
•
Filing: 1998-12-09
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Granted: 2001-01-30
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Expires: 2018-12-09
Abstract
Abstract Chemical vapor deposition is used to form a film of Bi oxide, Sr oxide, and Ta oxide on a heated substrate by decomposing the precursors of these oxides at the surface of the substrate. The precursor of Bi oxide is a Bi complex which includes at least one carboxylate group and is decomposed and deposited at a temperature lower than 450° C. The film of Bi, Sr, and Ta oxides obtained by low-temperature CVD is predominantly non-ferroelectric, but can be converted into a ferroelectric film by a subsequent heating process.
Inventors
- 👤 Frank S. Hintermaier
- 👤 Peter C. Van Buskirk
- 👤 Jeffrey F. Roeder
- 👤 Bryan C. Hendrix
- 👤 Thomas H. Baum
- 👤 Debra A. Desrochers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 15:07
CPC Classifications
H; H10; H10P; H10P14/00; H10P14/60; H10P14/66; H10P14/668; C; C23; C23C; C23C16/00; C23C16/22; C23C16/30; C23C16/40; C23C16/407; C23C16/56; C30; C30B; C30B25/00; C30B25/02; C30B29/00; C30B29/10; C30B29/16; H10D; H10D1/00; H10D1/60; H10D1/68; H10D1/682; H10P14/63; H10P14/6326; H10P14/6328; H10P14/6334; H10P14/69; H10P14/692; H10P14/6938; H10P14/69398
Claims Analysis
Total Claims: 73
Claim 1
Independent Claim
45 words
A method of forming a film comprising Bi oxide on a substrate, said method comprising: decomposing a precursor of Bi oxide to form Bi oxide, wherein said precursor of Bi oxide comprises at least one carboxylate group; and depositing said Bi oxide on said substrate.
Claim 2
Independent Claim
45 words
A method of forming a film comprising Bi oxide on a substrate, said method comprising: decomposing a precursor of Bi oxide to form Bi oxide, wherein said precursor of Bi oxide comprises at least one carboxylate group; and depositing said Bi oxide on said substrate.
Claim 3
Dependent Claim
27 words
The method of claim 1 , wherein said step of decomposing said precursor and depositing said Bi oxide takes place at a temperature lower than 450° C.
Claim 4
Dependent Claim
21 words
The method of claim 1 , wherein said precursor of Bi oxide is dissolved in a solution prior to being decomposed.
Claim 5
Dependent Claim
54 words
The method of claim 1 , further comprising: decomposing a precursor of Sr oxide and a precursor of Ta oxide at a temperature lower than 450° C. to form Sr oxide and Ta oxide, respectively; and depositing said Sr oxide and said Ta oxide on said substrate at a temperature lower than 450° C.
Claim 6
Dependent Claim
117 words
The method of claim 4 , wherein said film comprises a compound selected from the group consisting of: SrBi 2 Ta 2 O 9 ; SrBi 2 Ta 2-x Nb x O 9 , wherein 0≦x≦2; SrBi 2 Nb 2 O 9 ; Sr 1-x Ba x Bi 2 Ta 2-y Nb y O 9 , wherein 0≦x≦1 and 0≦y≦2; Sr 1-x Ca x Bi 2 Ta 2-y Nb y O 9 wherein 0≦x≦1, and 0≦y≦2; Sr 1-x Pb x Bi 2 Ta 2-y Nb y O 9 , wherein 0≦x≦1, and 0≦y≦2; and Sr 1-x-y-z Ba x Ca y Pb z Bi 2 Ta 2-p Nb p O 9 , wherein 0≦x≦1, 0≦y≦1, 0≦z≦1, and 0≦p≦2.
Claim 7
Dependent Claim
32 words
The method of claim 5 , wherein at least one element of said compound is substituted by a metal selected from the group consisting of Ce, La, Pr, Ho, Eu, and Yb.
Claim 8
Dependent Claim
50 words
The method of claim 4 , wherein said precursor of Ta oxide has the formula Ta(OR) 5-n (X) n , wherein R is Me, Et, Pr, i Pr, Bu, i Bu, t Bu, pentyl, or pentyl, wherein X is β-diketonate, and wherein n is 1, 2, 3, 4, or 5.
Claim 9
Dependent Claim
18 words
The method of claim 7 , wherein said precursor of Ta oxide is Ta(O i Pr) 4 (thd).
Claim 10
Dependent Claim
72 words
The method of claim 4 , wherein said method further comprises: placing said substrate in a chamber; heating said substrate to a deposition temperature lower than 450° C.; introducing vapors of said precursor of Bi oxide, said precursor of Sr oxide, and said precursor of Ta oxide into said chamber; decomposing said precursors of Bi oxide, Sr oxide, and Ta oxide into said oxides thereof; and depositing said oxides on said substrate.
Claim 11
Dependent Claim
35 words
The method of claim 9 , wherein said substrate is heated inside said chamber at a temperature lower than 450° C. in the presence of at least one of O 2 and O 3 .
Claim 12
Dependent Claim
24 words
The method of claim 9 , wherein said substrate is heated inside said chamber at a temperature lower than 450° C. at least twice.
Claim 13
Dependent Claim
22 words
The method of claim 9 , wherein the pressure in said chamber is varied while said substrate is positioned in said chamber.
Claim 14
Dependent Claim
20 words
The method of claim 9 , wherein said deposition temperature is varied while said substrate is positioned in said chamber.
Claim 15
Dependent Claim
26 words
The method of claim 9 , wherein at least one of said processes of heating, decomposing, and depositing is performed at least twice on said substrate.
Claim 16
Dependent Claim
29 words
The method of claim 9 , wherein the decomposition of said precursors comprises: introducing an oxidizer into said chamber; and converting said precursors into said oxides by oxidative decomposition.
Claim 17
Dependent Claim
49 words
The method of claim 15 , wherein said vapors of said precursors, said oxidizers, and an inert gas comprising at least one of Ar, He, and N 2 are introduced to said chamber at a total flow rate of 1 ml/min to 15,000 ml/minute, measured at the standard condition.
Claim 18
Dependent Claim
22 words
The method of claim 15 , wherein the composition of said oxidizer is varied while said substrate is positioned in said chamber.
Claim 19
Dependent Claim
26 words
The method of claim 15 , wherein said substrate is removed from said chamber, treated by at least one intermediate process, and returned to said chamber.
Claim 20
Dependent Claim
30 words
The method of claim 15 , wherein said substrate is flushed with a mixture of an inert gas and said oxidizer after being exposed to said vapors of said precursors.
Claim 21
Dependent Claim
34 words
The method of claim 15 , wherein said substrate is flushed with a mixture of an inert gas and said oxidizer before being exposed to said vapors of said precursors of said metal oxides.
Claim 22
Dependent Claim
24 words
The method of claim 4 , wherein said oxides are deposited onto said substrate over a time period between 2 minutes and 2 hours.
Claim 23
Dependent Claim
24 words
The method of claim 21 , wherein said oxides are deposited onto said substrate over a time period between 2 minutes and 15 minutes.
Claim 24
Dependent Claim
51 words
The method of claim 15 , wherein an additional inert gas is added to said chamber, said inert gas comprising at least one of Ar, He, and N 2 , and wherein said additional inert gas occupies between 10% and 90% of the total gas and vapor flow into said chamber.
Claim 25
Dependent Claim
38 words
The method of claim 15 , wherein said oxidizer is formed by converting a molecule in said chamber into an active oxidizer by applying at least one of a plasma, UV light, heat, a sensitizer, and ion beams.
Claim 26
Dependent Claim
17 words
The method of claim 15 , wherein at least two different oxidizers are introduced into said chamber.
Claim 27
Dependent Claim
20 words
The method of claim 25 , wherein said oxidizer comprises at least one of O 2 and N 2 O.
Claim 28
Dependent Claim
46 words
The method of claim 15 , wherein said oxidizer comprises at least one of O 2 , singlet O 2 , O 3 , H 2 O 2 , N 2 O, NO x , where x is 1, 2, or 3, and downstream oxygen plasma.
Claim 29
Dependent Claim
24 words
The method of claim 27 , wherein said oxidizer occupies between 5% and 95% of the total gas and vapor flow into said chamber.
Claim 30
Dependent Claim
19 words
The method of claim 9 , wherein the pressure in said chamber is between 0.001 torr and 760 torr.
Claim 31
Dependent Claim
19 words
The method of claim 29 , wherein the pressure in said chamber is between 0.1 torr and 10 torr.
Claim 32
Dependent Claim
20 words
The method of claim 9 , wherein said oxides are deposited at a temperature between 300° C. and 450° C.
Claim 33
Dependent Claim
19 words
The method of claim 4 , wherein said precursor of Sr oxide is Sr(thd) 2 or Sr(thd) 2 adduct.
Claim 34
Dependent Claim
22 words
The method of claim 32 , wherein said precursor of Sr oxide comprises at least one of a polyether and a polyamine.
Claim 35
Dependent Claim
38 words
The method of claim 33 , wherein said polyether has the formula R—O—(CH 2 CH 2 O) n —R′, wherein 2≦n≦6, and wherein each of R and R′ is, independently, an alkyl group, an aryl group, or hydrogen.
Claim 36
Dependent Claim
46 words
The method of claim 33 , wherein said polyamine has the formula R—NR″—(CH 2 CH 2 NR″) n —R′) wherein 2≦n≦6, wherein each of R and R′ is, independently, an alkyl group, an aryl group, or hydrogen, and wherein R″ is H, Me, Et or Pr.
Claim 37
Dependent Claim
22 words
The method of claim 33 , wherein said precursor of Sr oxide comprises at least one of tetraglyme, triglyme, N,N,N′,N″,N″-pentamethyl-diethylene-triamine, and N,N,N′,N″,N′″,N′″-hexamethyl-triethylene-tetramine.
Claim 38
Dependent Claim
53 words
The method of claim 4 , wherein at least one of said precursors is dissolved in a solution comprising at least one of an aliphatic, cycloaliphatic, and an aromatic solvent, said solvent having at least one functional group selected from the group consisting of an alcohol, ether, ester, amine, ketone, and aldehyde group.
Claim 39
Dependent Claim
22 words
The method of claim 37 , wherein said precursors of Bi oxide, Sr oxide, and Ta oxide are dissolved in said solution.
Claim 40
Dependent Claim
11 words
The method of claim 38 , wherein said solvent is butylacetate.
Claim 41
Dependent Claim
27 words
The method of claim 37 , wherein said solution comprises a mixture of THF, i PrOH, and a Lewis base in a ratio of about 8:2:1, respectively.
Claim 42
Dependent Claim
25 words
The method of claim 40 , wherein the composition of said precursors in said mixture is varied while said substrate is positioned in said chamber.
Claim 43
Dependent Claim
23 words
The method of claim 37 , wherein said solution comprises a mixture of octane, decane, and pentamethyl-diethylene-triamine in a ratio of about 5:4:1.
Claim 44
Dependent Claim
16 words
The method of claim 37 , wherein said solution is evaporated by at least one vaporizer.
Claim 45
Dependent Claim
20 words
The method of claim 43 , wherein said solution is evaporated at a temperature from 130° C. to 300° C.
Claim 46
Dependent Claim
20 words
The method of claim 43 , wherein said solution is evaporated at a temperature from 170° C. to 240° C.
Claim 47
Dependent Claim
46 words
The method of claim 43 , wherein an inert gas is added to the vapors of said solution and a mixture of said inert gas and vapors is delivered to said chamber, said inert gas comprising at least one of Ar, He, and N 2 .
Claim 48
Dependent Claim
29 words
The method of claim 46 , wherein said mixture comprises vapors of said precursors of Bi oxide, Sr oxide, and Ta oxide in a ratio of about 2:1:2, respectively.
Claim 49
Dependent Claim
26 words
The method of claim 46 , wherein the composition of said inert gas in said mixture is varied while said substrate is positioned in said chamber.
Claim 50
Dependent Claim
33 words
The method of claim 43 , wherein vapors consisting essentially of said precursor of Bi oxide are delivered to said chamber during a period between the onset of deposition and 30 minutes thereafter.
Claim 51
Dependent Claim
19 words
The method of claim 1 , further comprising converting said film into a ferroelectric film by an annealing process.
Claim 52
Dependent Claim
30 words
The method of claim 50 , wherein said film is heated to a temperature between 600° C. and 800° C. for a time period between 5 minutes and 3 hours.
Claim 53
Dependent Claim
15 words
The method of claim 1 , wherein said film is deposited as a ferroelectric film.
Claim 54
Dependent Claim
50 words
The method of claim 1 , wherein said precursor of Bi oxide has the formula Bi(O 2 CR) 3 , Bi(O 2 CR) 2 (O 2 CR′), or Bi(O 2 CR)(O 2 CR′)(O 2 CR″), wherein each of R, R′, and R″ is, independently, an alkyl or an aryl group.
Claim 55
Dependent Claim
35 words
The method of claim 53 , wherein said precursor of Bi oxide is Bi(O 2 CC(CH 3 ) 3 ) 3 , Bi(O 2 CPh) 3 , or Bi(O 2 C t Bu) 3 .
Claim 56
Dependent Claim
51 words
The method of claim 1 , wherein said precursor of Bi oxide is Bi(O 2 CR) 3 , wherein R is t pentyl, pentyl, t Bu, Bu, i Pr, Pr, Et, Me, Ph, aryl, or SiR″ 3 , and wherein R″ is t Bu, Bu, i Pr, Pr, Et, or Me.
Claim 57
Dependent Claim
23 words
The method of claim 1 , wherein said precursor of Bi oxide comprises an alkoxy group, a phenoxy group, or a silyl group.
Claim 58
Dependent Claim
26 words
The method of claim 1 , wherein said precursor of Bi oxide comprises a donor atom selected from the group consisting of N, O, and S.
Claim 59
Dependent Claim
33 words
The method of claim 1 , wherein said film comprises at least one of Ca, Ba, Pb, Na, Fe, Al, Sc, Y, Ti, Nb, W, Mo, Ce, La, Pr, Ho, Eu, and Yb.
Claim 60
Dependent Claim
130 words
The method of claim 58 , wherein said film comprises a compound having the formula (Bi 2 O 2 ) 2+ (A m−1 B m O 3m+1 ) 2− , wherein A is Bi 3+ , L 3+ , L 2+ , Ca 2+ , Sr 2+ , Ba 2+ , Pb 2+ , or Na + , B is Fe 3+ , A 3+ , Sc 3+ , Y 3+ , L 3+ , L 4+ , Ti 4+ , Nb 5+ , Ta 5+ , W 6+ , or Mo 6+ , wherein L is selected from the group consisting of Ce 4+ , La 3+ , Pr 3+ , Ho 3+ , Eu 2+ and Yb 2+ , and m is 1, 2, 3, 4, or 5.
Claim 61
Dependent Claim
117 words
The method of claim 1 , wherein said film comprises a compound selected from the group consisting of: Bi 2 WO 6 ; BiMO 3 , where M is Fe or Mn; Ba 2 BiMO 6 , where M is V, Nb or Ta; Pb 2 BiMO 6 , where M is V, Nb or Ta; Ba 3 Bi 2 MO 9 , where M is Mo or W; Pb 3 Bi 2 MO 9 , where M is Mo or W; Ba 6 BiMO 18 , where M is Mo or W; Pb 6 BiMO 18 , where M is Mo or W; KBiTi 2 O 6 ; and K 2 BiNb 5 O 15 .
Claim 62
Dependent Claim
47 words
The method of claim 1 , wherein said substrate comprises at least one of Si, n-doped Si, p-doped Si, SiO 2 , Si 3 N 4 , GaAs, MgO, Al 2 O 3 , ZrO 2 , SrTiO 3 , BaTiO 3 , and PbTiO 3 .
Claim 63
Dependent Claim
36 words
The method of claim 1 , wherein said film is deposited on a bottom electrode disposed on said substrate, said substrate comprising a transistor therein, said bottom electrode being connected to said transistor by a plug.
Claim 64
Dependent Claim
120 words
The method of claim 62 , wherein said bottom electrode comprises at least one of: a metal selected from the group consisting of Pt, Pd, Au, Ir, and Rh; a conducting metal oxide selected from the group consisting of IrO x , RhO x , RuO x , OsO x , ReO x , WO x , wherein x is 0, 1 or 2; a conducting metal nitride selected from the group consisting of TiN x , ZrN x , and WN y TaN y , wherein 0≦x≦1.0 and 0≦y≦1.7; and a superconducting oxide selected from the group consisting of YBa 2 Cu 3 O 7-x wherein 0≦x≦1, and Bi 2 Sr 2 Ca 2 Cu 3 O 10 .
Claim 65
Dependent Claim
14 words
The method of claim 62 , wherein said bottom electrode is a Pt electrode.
Claim 66
Dependent Claim
39 words
The method of claim 62 , wherein at least one first intermediate layer is provided between said bottom electrode and said plug, said first intermediate layer comprising at least one of an adhesion layer and a diffusion barrier layer.
Claim 67
Dependent Claim
43 words
The method of claim 62 , wherein at least one second intermediate layer is provided between said bottom electrode and said metal oxide film, said second intermediate layer comprising at least one of a seed layer, a conducting layer, and a dielectric layer.
Claim 68
Dependent Claim
33 words
The method of claim 62 , wherein said plug is connected to said bottom electrode and to a drain of a MOS ferroelectric effect transistor, said plug consisting essentially of W or Si.
Claim 69
Dependent Claim
20 words
The method of claim 62 , wherein said film is used as a thin ferroelectric film for a ferroelectric capacitor.
Claim 70
Dependent Claim
20 words
The method of claim 62 , wherein said film is used as a thin ferroelectric film for a ferroelectric memory.
Claim 71
Dependent Claim
22 words
The method of claim 69 , wherein said film is used as a thin ferroelectric film for a ferroelectric field effect transistor.
Claim 72
Independent Claim
70 words
A method of forming a film on a substrate, said method comprising: heating said substrate to a temperature lower than 450° C.; and introducing vapors of a precursor of Bi oxide to said substrate, wherein said precursor of Bi oxide comprises at least one carboxylate group, said precursor decomposing at the surface of said substrate to form Bi oxide, said Bi oxide being deposited on the surface of said substrate.
Claim 73
Independent Claim
70 words
A method of forming a film on a substrate, said method comprising: heating said substrate to a temperature lower than 450° C.; and introducing vapors of a precursor of Bi oxide to said substrate, wherein said precursor of Bi oxide comprises at least one carboxylate group, said precursor decomposing at the surface of said substrate to form Bi oxide, said Bi oxide being deposited on the surface of said substrate.
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