Preparation of lanthanide-containing precursors and deposition of lanthanide-containing films
Methods and compositions for depositing rare earth metal-containing layers are described herein. In general, the disclosed methods deposit the precursor compounds comprising rare earth-containing compounds using deposition methods such as chemical vapor deposition or atomic layer deposition. The disclosed precursor compounds include a cyclopentadienyl ligand having at least one aliphatic group as a substituent and an amidine ligand.
1. A method for depositing a lanthanide-containing film on a semiconductor substrate, the method comprising:
a) providing a substrate;
b) providing the lanthanide-containing precursor of the general formula:
Ln(R 1 C p ) m (R 2 —N—C(R 4 )═N—R 2 ) n ,
wherein:
Ln is a lanthanide metal having an ionic radius from approximately 0.75 Å to approximately 0.94 Å, a 3+ charge, and a coordination number of 6;
R 1 is selected from the group consisting of H and a C1-C5 alkyl chain;
R 2 is selected from the group consisting of H and a C1-C5 alkyl chain;
R 4 is selected from the group consisting of H and Me;
n and m range from 1 to 2; and
c) depositing a lanthanide-containing film on the substrate.
2. The method of claim 1 , further comprising depositing the lanthanide-containing film on the substrate at a temperature between about 150° C. and about 600° C.
3. The method of claim 1 , further comprising depositing the lanthanide-containing film on the substrate at a pressure between about 0.5 mTorr and about 20 Torr.
4. The method of claim 1 , wherein the lanthanide-containing precursor is a liquid at a temperature below about 70° C.
5. The method of claim 4 , wherein the lanthanide-containing precursor is a liquid at a temperature below about 40° C.
6. The method of claim 1 , wherein the lanthanide-containing film is selected from the group consisting of Ln 2 O 3 , (LnLn′)O 3 , Ln 2 O 3 -Ln′ 2 O 3 , LnSi x O y , LnGe x O y , (Al,Ga,Mn)LnO 3 , HfLnO x , and ZrLnO x , wherein Ln and Ln′ are different.
7. The method of claim 6 , wherein the lanthanide-containing film is selected from the group consisting of HfErO x , ZrErO x , HfYbO x , and ZrYbO x .
8. The method of claim 1 , wherein the lanthanide-containing precursor has the general formula selected from the group consisting of Ln(R 1 Cp) 2 (N Z -fmd), Ln(R 1 Cp) 2 (N Z -amd), Ln(R 1 Cp)(N Z -fmd) 2 , and Ln(R 1 Cp)(N Z -amd) 2 , wherein Ln is selected from the group consisting of Y, Gd, Dy, Er, and Yb; R 1 is selected from the group consisting of Me, Et, and iPr; and Z is iPr or tBu.
9. A method of forming a lanthanide-containing film on a substrate, the method comprising the steps of: providing a reactor having at least one substrate disposed therein; introducing at least one lanthanide-containing precursor of the general formula:
Ln(R 1 C p ) m (R 2 —N—C(R 4 )═N—R 2 ) n ,
wherein:
Ln is a lanthanide metal having an ionic radius from approximately 0.75 Å to approximately 0.94 Å, a 3+ charge, and a coordination number of 6;
R 1 is selected from the group consisting of H and a C1-C5 alkyl chain;
R 2 is selected from the group consisting of H and a C1-C5 alkyl chain;
R 4 is selected from the group consisting of H and Me;
n and m range from 1 to 2 into the reactor; and contacting the lanthanide-containing precursor and the substrate to form a lanthanide-containing layer on at least one surface of the substrate using a deposition process.
10. The method of claim 9 , further comprising the steps of:
a) providing at least one reactant species into the reactor, wherein said reactant species is an oxygen containing fluid; and
b) reacting said lanthanide-containing precursor with said reactant species.
11. The method of claim 10 , wherein the at least one reactant species is selected from the group consisting of O 2 , O 3 , H 2 O, H 2 O 2 , acetic acid, formalin, para-formaldehyde, and combinations thereof.
12. The method of claim 10 , wherein the lanthanide-containing precursor and the reactant species are either introduced at least partially simultaneously as in a chemical vapor deposition process, or are introduced at least partially sequentially as in an atomic layer deposition process.
13. The method of claim 10 , further comprising introducing a metal precursor into the reactor, wherein the metal precursor is different than the lanthanide-containing precursor and depositing at least part of the metal precursor to form the lanthanide-containing layer on the one or more substrates.
14. The method of claim 13 , wherein a metal of the metal precursor is selected from the group consisting of Hf, Si, Al, Ga, Mn, Ti, Ta, Bi, Zr, Pb, Nb, Mg, Sr, Y, Ba, Ca, a lanthanide, and combinations thereof.
15. The method of claim 9 , wherein the deposition process is a chemical vapor deposition process.
16. The method of claim 9 , wherein the deposition process is an atomic layer deposition process having a plurality of deposition cycles.
17. The method of claim 9 , wherein the lanthanide-containing precursor has the general formula selected from the group consisting of Ln(R 1 Cp) 2 (N Z -fmd), Ln(R 1 Cp) 2 (N Z -amd), Ln(R 1 Cp)(N Z -fmd) 2 , and Ln(R 1 Cp)(N Z -amd) 2 , wherein Ln is selected from the group consisting of Y, Gd, Dy, Er, and Yb; R 1 is selected from the group consisting of Me, Et, and iPr; and Z is iPr or tBu.
18. A lanthanide-containing film coated substrate comprising the product of the method of claim 9 .