US2011293830A1PendingUtilityA1

Precursors and methods for atomic layer deposition of transition metal oxides

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Assignee: HATANPAA TIMOPriority: Feb 25, 2010Filed: Feb 24, 2011Published: Dec 1, 2011
Est. expiryFeb 25, 2030(~3.6 yrs left)· nominal 20-yr term from priority
Inventors:Timo HatanpääJaakko NiinistoMikko RitalaMarkku LeskeläSuvi Haukka
C23C 16/405C23C 16/45536C23C 16/45553C01P 2006/40C01G 27/02C01G 25/02C23C 16/45527C01G 23/07C07F 17/00C07F 7/00
59
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Claims

Abstract

Methods are provided herein for forming transition metal oxide thin films, preferably Group IVB metal oxide thin films, by atomic layer deposition. The metal oxide thin films can be deposited at high temperatures using metalorganic reactants. Metalorganic reactants comprising two ligands, at least one of which is a cycloheptatriene or cycloheptatrienyl (CHT) ligand are used in some embodiments. The metal oxide thin films can be used, for example, as dielectric oxides in transistors, flash devices, capacitors, integrated circuits, and other semiconductor applications.

Claims

exact text as granted — not AI-modified
1 . A method for forming a transition metal oxide thin film on a substrate in a reaction chamber by atomic layer deposition, the method comprising:
 providing a vapor phase pulse of a first metalorganic reactant comprising a CHT ligand and a transition metal to the reaction chamber such that it forms no more than a monolayer on the substrate;   removing excess first reactant from the reaction chamber;   providing a vapor phase pulse of a second reactant comprising oxygen to the reaction chamber; and   removing excess second reactant and any reaction byproducts from the reaction chamber;   wherein the providing and removing steps are repeated until a thin metal oxide film of a desired thickness and composition is obtained, wherein the substrate temperature during the providing and removing steps is above about 300° C.   
     
     
         2 . The method of  claim 1 , wherein the metalorganic reactant comprises a Group IVB metal. 
     
     
         3 . The method of  claim 1 , wherein the substrate temperature during the providing and removing steps is above about 350° C. 
     
     
         4 . The method of  claim 1 , wherein the metalorganic reactant comprises one or more of hafnium, titanium, and zirconium. 
     
     
         5 . The method of  claim 1 , wherein the metalorganic reactant is an organometallic reactant. 
     
     
         6 . The method of  claim 1 , wherein the metalorganic reactant comprises two ligands, one of which is the cycloheptatrienyl (CHT, C 7 H 7 ) ligand. 
     
     
         7 . The method of  claim 6 , wherein the metalorganic reactant comprises two CHT ligands. 
     
     
         8 . The method of  claim 6 , wherein the metalorganic reactant comprises one CHT ligand and one cyclopentadienyl (Cp) ligand. 
     
     
         9 . The method of  claim 6 , wherein the metalorganic reactant does not comprise a halide. 
     
     
         10 . The method of  claim 4 , wherein the deposited thin film comprises ZrO 2 . 
     
     
         11 . The method of  claim 4 , wherein the deposited thin film comprises TiO 2 . 
     
     
         12 . The method of  claim 4 , wherein the deposited thin film comprises HfO 2 . 
     
     
         13 . A method for forming a transition metal oxide thin film by atomic layer deposition on a substrate in a reaction chamber comprising:
 alternately and sequentially contacting the substrate with a vapor phase reactant pulse comprising a metal reactant and a vapor phase reactant pulse comprising an oxygen reactant,   wherein the metal reactant comprises a transition metal and two ligands, one of which is a cycloheptatrienyl (CHT) ligand.   
     
     
         14 . The method of  claim 13 , wherein the metal reactant comprises a Group IVB metal. 
     
     
         15 . The method of  claim 13 , wherein the metal reactant is selected from reactants having the formula (I) R x Cp-M-CHT, where RxCp represents substituted or unsubstituted cyclopentadienyl, CHT is cycloheptatrienyl and M is selected from Ti, Zr and Hf. 
     
     
         16 . The method of  claim 13 , wherein the metal reactant is selected from reactants having the formula (II) (R 1 R 2 R 3 R 4 R 5 R 6 R 7 )CHT-M-Cp(R 8 R 9 R 10 R 11 R 12 ), where M is selected from Ti, Zr and Hf, and R 1-12  can independently be H or an alkyl group. 
     
     
         17 . The method of  claim 13 , wherein the metal reactant is selected from reactants having the formula (III) (R 1 R 2 R 3 R 4 R 5 R 6 R 7 )CHT-M-CHT(R 8 R 9 R 10 R 11 R 12 R 13 R 14 ), where M is selected from Ti, Zr and Hf, and R 1-14  can independently be H or an alkyl group. 
     
     
         18 . The method of  claim 13 , wherein the metal reactant is selected from reactants having the formula (IV) R 1 R 2 R 3 R 4 R 5 R 6 R 7 )CHT-M-L, where M is selected from Ti, Zr and Hf; R 1-7  can independently be H or an alkyl group; and L is a mono or bidentate alkyl, cycloalkyl, alkoxy, amide or imido group or acyclic or cyclic dienyl ligand. 
     
     
         19 . The method of  claim 13 , wherein the metal reactant is selected from reactants having the formula (V) R 1 R 2 R 3 R 4 R 5 R 6 R 7 )CHT-M-CHD(R 8 R 9 R 10 R 11 R 12 R 13 R 14 R 15 R 16 ), where M is selected from Ti, Zr and Hf; R 1-16  can independently be H or an alkyl group, and CHD is cyloheptadiene (C 7 H 9 ). 
     
     
         20 . The method of  claim 13 , wherein the metal reactant is selected from reactants having the formula (VI) (R 1 R 2 R 3 R 4 R 5 R 6 R 7 R 8 )X-M-X(R 9 R 10 R 11 R 12 R 13 R 14 R 15 R 16 ), where M is selected from Ti, Zr and Hf, R 1-14  can independently be H or an alkyl group and X is cycloheptatriene (C 7 H 8 ). 
     
     
         21 . The method of  claim 13 , wherein the oxygen reactant is selected from the group consisting of O 2 , O 3 , H 2 O, NO, NO 2 , N 2 O, and H 2 O 2 . 
     
     
         22 . The method of  claim 13 , wherein the substrate temperature during the pulses is from about 100 to about 500° C. 
     
     
         23 . The method of  claim 13 , wherein the substrate temperature during the pulses is above about 300° C. 
     
     
         24 . The method of  claim 13 , wherein the metal precursor comprises Ti. 
     
     
         25 . The method of  claim 13 , wherein the metal precursor comprises Hf. 
     
     
         26 . The method of  claim 13 , wherein the metal precursor comprises Zr. 
     
     
         27 . A method for forming a thin film comprising a transition metal by atomic layer deposition on a substrate in a reaction space comprising:
 alternately and sequentially contacting the substrate with a first vapor phase metal reactant pulse and a second vapor phase reactant pulse;   wherein the alternate and sequential pulses are repeated until a thin film of a desired thickness and composition is obtained and wherein the metal reactant comprises a compound comprising a transition metal and two cycloheptatriene (C 7 H 8 ) ligands.   
     
     
         28 . The method of  claim 27 , wherein the metal reactant comprises a Group IVB metal. 
     
     
         29 . The method of  claim 28 , wherein the metal reactant comprises one of Ti, Hf and Zr. 
     
     
         30 . The method of  claim 27 , wherein the substrate temperature during the pulses is above about 300° C. 
     
     
         31 . The method of  claim 27 , wherein the thin film comprises a metal oxide. 
     
     
         32 . The method of  claim 31 , wherein the second reactant is an oxygen source. 
     
     
         33 . The method of  claim 32 , wherein the second reactant comprises one or more of O 2 , H 2 O, O 3 , NO, NO 2 , N 2 O, and H 2 O 2 . 
     
     
         34 . The method of  claim 27 , wherein the thin film comprises a metal nitride. 
     
     
         35 . The method of  claim 34 , wherein the second reactant is a nitrogen source. 
     
     
         36 . The method of  claim 35 , wherein the nitrogen source is selected from NH 3 , N 2 H 2 , and nitrogen containing plasma. 
     
     
         37 . A method of synthesizing a CHT metal reactant comprising a transition metal, the method comprising forming a reaction mixture by combining a transition metal reactant with ferric chloride, cycloheptatriene and tetrahydrofuran (THF) in a flask containing magnesium chips. 
     
     
         38 . The method of  claim 37 , wherein the reaction mixture is stirred overnight. 
     
     
         39 . The method of  claim 37 , wherein the ferric chloride, cycloheptatriene and THF are first combined and then the transition metal chloride is added. 
     
     
         40 . The method of  claim 39 , wherein the transition metal chloride is added while warming the mixture. 
     
     
         41 . The method of  claim 39 , wherein the transition metal reactant is a transition metal chloride. 
     
     
         42 . The method of  claim 37 , wherein the transition metal reactant is a Group IVB metal chloride. 
     
     
         43 . The method of  claim 37 , wherein the Group IVB metal chloride is TiCl 4 . 
     
     
         44 . The method of  claim 37 , wherein the CHT metal reactant comprises (C 7 H 7 )M(C 7 H 9 )/M(C 7 H 8 ) (CHT-M-CHD).

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