Preparation of cerium-containing precursors and deposition of cerium-containing films

Abstract

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 composition comprising a lanthanide-containing precursor of the general formula:
   Ln(R 1 Cp) m (R 2 —N—C(R 4 )═N—R 2 ) n ,
   
       wherein:
 Ln=Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu; 
 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 
 the precursor has a melting point below approximately 105° C. 
 
     
     
         2 . The composition of  claim 1 , wherein R 1  is selected from the group consisting of Me, Et, and iPr. 
     
     
         3 . The composition of  claim 1 , wherein R 2  is selected from the group consisting of iPr and tBu. 
     
     
         4 . The composition of  claim 1 , wherein the lanthanide-containing precursor is Ce(iPrCp) 2 (iPr-N—C(H)=N-iPr). 
     
     
         5 . The composition of  claim 1 , wherein the lanthanide-containing precursor is Pr(iPrCp) 2 (iPr-N—C(H)=N-iPr). 
     
     
         6 . 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  claim 1 ; and   c) depositing a lanthanide-containing film on the substrate.   
     
     
         7 . The method of  claim 6 , further comprising depositing the lanthanide-containing film on the substrate at a temperature between about 150° C. and about 600° C. 
     
     
         8 . The method of  claim 7 , further comprising depositing the lanthanide-containing film on the substrate at a pressure between about 0.5 mTorr and about 20 Torr. 
     
     
         9 . The method of  claim 6 , wherein the lanthanide-containing precursor is a liquid at a temperature below about 70° C. 
     
     
         10 . The method of  claim 9 , wherein the lanthanide-containing precursor is a liquid at a temperature below about 40° C. 
     
     
         11 . The method of  claim 6 , 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. 
     
     
         12 . The method of  claim 6 , wherein the lanthanide-containing precursor is Ce(iPrCp) 2 (iPr-N—C(H)=N-iPr). 
     
     
         13 . The method of  claim 6 , wherein the lanthanide-containing precursor is Pr(iPrCp) 2 (iPr-N—C(H)=N-iPr). 
     
     
         14 . 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  claim 1  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. 
     
     
         15 . The method of  claim 14 , 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.   
     
     
         16 . The method of  claim 15 , 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. 
     
     
         17 . The method of  claim 15 , 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. 
     
     
         18 . The method of  claim 14 , 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. 
     
     
         19 . The method of  claim 18 , 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. 
     
     
         20 . The method of  claim 14 , wherein the deposition process is a chemical vapor deposition process. 
     
     
         21 . The method of  claim 14 , wherein the deposition process is an atomic layer deposition process having a plurality of deposition cycles. 
     
     
         22 . The method of  claim 14 , wherein the lanthanide-containing precursor is Ce(iPrCp) 2 (iPr-N—C(H)=N-iPr). 
     
     
         23 . The method of  claim 14 , wherein the lanthanide-containing precursor is Pr(iPrCp) 2 (iPr-N—C(H)=N-iPr).