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

A composition comprising a combination of at least two organometallic compounds, wherein each of the organometallic compounds is represented by Formula I:

• Rx—Sn-A4-x Formula I
• wherein:
• A is selected from the group consisting of(YaR′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.

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:
• Rx—Sn-A4-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.

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-A4-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.