Organometallic compounds and methods for the deposition of high purity tin oxide

Abstract

Disclosed herein are compounds useful for the deposition of high purity tin oxide. Also disclose are methods for the deposition of tin oxide films using such compounds. Such films demonstrate high conformality, high etch selectivity and are optically transparent. Such compounds are those of the Formula as follows R x —Sn-A 4-x wherein: A is selected from the group consisting of (Y a R′ z ) and a 3- to 7-membered N-containing heterocyclic group; each R group is independently selected from the group consisting of an alkyl or aryl group having from 1 to 10 carbon atoms; each R′ group is independently selected from the group consisting of an alkyl, acyl or aryl group having from 1 to 10 carbon atoms; x is an integer from 0 to 4; a is an integer from 0 to 1; Y is selected from the group consisting of N, O, S, and P; and z is 1 when Y is O, S or when Y is absent and z is 2 when Y is N or P.

1 . An organometallic compound of Formula 1:
   R x —Sn-A 4-x   Formula I
   
       wherein:
 A is selected from the group consisting of (Y a R′ z ) and a saturated 3- to 7-membered N-containing heterocyclic group; 
 each R group is independently selected from the group consisting of an alkyl or aryl group having from 1 to 10 carbon atoms; 
 each R′ group is independently selected from the group consisting of an alkyl, acyl or aryl group having from 1 to 10 carbon atoms; 
 x is an integer from 0 to 4; 
 a is an integer from 0 to 1; 
 Y is selected from the group consisting of N, O, and P; and 
 z is 1 when Y is O or when Y is absent and z is 2 when Y is N or P, 
 wherein when Y is N, R′ represents a combination of two different alkyl, acyl, or aryl groups, and wherein when Y is O, x is 2. 
 
     
     
         2 . The organometallic compound of  claim 1 , wherein A is selected from the group consisting of an (NR′ 2 ) group and a saturated 3- to 7-membered N-containing heterocyclic group. 
     
     
         3 . The organometallic compound of  claim 2 , wherein A is an (NR′ 2 ) group. 
     
     
         4 . The organometallic compound of  claim 2 , wherein A is a saturated 3- to 7-membered N-containing heterocyclic group. 
     
     
         5 . The organometallic compound of  claim 4 , wherein A is a pyrrolidinyl group. 
     
     
         6 . The organometallic compound of  claim 1 , wherein A 4-x  is (NEtMe) 2 . 
     
     
         7 . The organometallic compound of  claim 1 , wherein each R and R′ group is an independently selected alkyl group having from 1 to 10 carbon atoms. 
     
     
         8 . The organometallic compound of  claim 7 , wherein each R and R′ group is an independently selected alkyl group having from 1 to 6 carbon atoms. 
     
     
         9 . The organometallic compound of  claim 8 , wherein each R and R′ group is an independently selected alkyl group having from 1 to 4 carbon atoms. 
     
     
         10 . The organometallic compound of  claim 1 , wherein each R and R′ is independently selected from the group consisting of methyl, ethyl, propyl, iso-propyl, tert-butyl, iso-butyl and n-butyl. 
     
     
         11 . The organometallic compound of  claim 1 , wherein R and R′ represent different alkyl groups. 
     
     
         12 . The organometallic compound of  claim 1 , wherein the compound of Formula I is selected from the group consisting of Me 2 Sn(NEtMe) 2 , t-BuSn(NEtMe) 3 , i-PrSn(NEtMe) 3 , n-PrSn(NEtMe) 3 , EtSn(NEtMe) 3 , i-BuSn(NEtMe) 3 , Et 2 Sn(NEtMe) 2 , Me 2 Sn(NEtMe) 2 , Sn(NEtMe) 4 , Bu 2 Sn(NEtMe) 2 , Sn(Pyrrolidinyl) 4  and Bu 2 Sn(Pyrrolidinyl) 2 . 
     
     
         13 . The organometallic compound of  claim 12 , wherein the compound of Formula I is selected from the group consisting of Me 2 Sn(NEtMe) 2 , Sn(Pyrrolidinyl) 4 ; and Bu 2 Sn(Pyrrolidinyl) 2 . 
     
     
         14 . The organometallic compound of  claim 13 , wherein the compound of Formula I is Me 2 Sn(NEtMe) 2 . 
     
     
         15 . A composition comprising a combination of at least two organometallic compounds, wherein each of the organometallic compounds is represented by Formula I:
   R x —Sn-A 4-x   Formula I
   
       wherein:
 A is selected from the group consisting of(Y a R′ 2 ) and a3- to 7-membered N-containing heterocyclic group; 
 each R group is independently selected from the group consisting of an alkyl or aryl group having from 1 to 10 carbon atoms; 
 each R′ group is independently selected from the group consisting of an alkyl, acyl or aryl group having from 1 to 10 carbon atoms; 
 x is an integer from 0 to 4; 
 a is an integer from 0 to 1; 
 Y is selected from the group consisting of N, O, and P; and 
 z is 1 when Y is O or when Y is absent and z is 2 when Y is N or P, 
 wherein at least one of the organometallic compounds is a compound represented by Formula I in which:
 Y is N, a is 1, and x is 2; or 
 Y is N, a is 1, and R′ represents a combination of two different alkyl, acyl, or aryl groups. 
 
 
     
     
         16 . The composition of  claim 15 , wherein at least one of the organometallic compounds is selected from the group consisting of MeSn(NMe 2 ) 3  and Sn(NMe 2 ) 4 . 
     
     
         17 . A method for the deposition of a tin oxide layer on a substrate by a vapour deposition process, the method comprising the steps of:
 a. providing at least one substrate having functional O—H groups covering the surface;   b. delivering to said substrate an organometallic compound in the gaseous phase;   c. delivering to said substrate an oxygen source in the gaseous phase;   d. activating the gaseous phase to form the tin oxide layer; and   e. repeating steps a to d to generate the desired thickness of the tin oxide layer, wherein the organometallic compound is of Formula I:
   R x —Sn-A 4-x   Formula I
 
   
       wherein:
 A is selected from the group consisting of (YaR′z) and a 3- to 7-membered N-containing heterocyclic group; 
 each R group is independently selected from the group consisting of an alkyl or aryl group having from 1 to 10 carbon atoms; 
 each R′ group is independently selected from the group consisting of an alkyl, acyl or aryl group having from 1 to 10 carbon atoms; 
 x is an integer from 0 to 4; 
 a is an integer from 0 to 1; 
 Y is selected from the group consisting of N, O, S, and P; and 
 z is 1 when Y is O, S or when Y is absent and z is 2 when Y is N or P. 
 
     
     
         18 . The method of  claim 17 , wherein the activation condition is plasma generation. 
     
     
         19 . A method for spacer-defined double patterning deposition, the method comprising the steps of:
 (a) depositing a layer of (photo)resist onto a substrate having functional O—H groups covering the surface, forming a pattern in the resist with electron-beam (e-beam) lithography, and developing the photoresist to give the pattern;   (b) depositing a spacer layer onto the resist using energy-enhanced ALD in the presence of an organometallic compound;   (c) performing an anisotropic etch to remove the tops of the features, using reactive ion etching (RIE) or ion milling (IM);   (d) removing the photoresist, either by a wet or plasma etch;   (e) anisotropically etching into the target layer; and   (f) removing the spacer, leaving the patterned substrate,   wherein the organometallic compound is of Formula I:
   Rx-Sn-A 4-x   Formula I
 
   
       wherein:
 A is selected from the group consisting of (Y a R′ z ) and a 3- to 7-membered N-containing heterocyclic group; 
 each R group is independently selected from the group consisting of an alkyl or aryl group having from 1 to 10 carbon atoms; 
 each R′ group is independently selected from the group consisting of an alkyl, acyl or aryl group having from 1 to 10 carbon atoms; 
 x is an integer from 0 to 4; 
 a is an integer from 0 to 1; 
 Y is selected from the group consisting of N, O, S, and P; and 
 z is 1 when Y is O, S or when Y is absent and z is 2 when Y is N or P. 
 
     
     
         20 . A method of using multistage distillation to purify the organometallic compound of  claim 1 . 
     
     
         21 . The method of  claim 19 , wherein 2 to 20 stages are required to reduce metal contamination to <1 ppm. 
     
     
         22 . The method of  claim 19 , wherein 2 to 20 stages are required to reduce metal contamination to <100 ppb. 
     
     
         23 . The method of  claim 19 , wherein 2 to 20 stages are required to reduce metal contamination to <10 ppb. 
     
     
         24 . The method of  claim 19 , wherein 2 to 20 stages are required to reduce metal contamination to 1 ppb or less.