Compositions and Methods for Forming a Semiconducting and/or Silicon-Containing Film, and Structures Formed Therefrom

Abstract

Compositions, inks and methods for forming a patterned silicon-containing film and patterned structures including such a film. The composition generally includes (a) passivated semiconductor nanoparticles and (b) first and second cyclic Group IVA compounds in which the cyclic species predominantly contains Si and/or Ge atoms. The ink generally includes the composition and a solvent in which the composition is soluble. The method generally includes the steps of (1) printing the composition or ink on a substrate to form a pattern, and (2) curing the patterned composition or ink. In an alternative embodiment, the method includes the steps of (i) curing either a semiconductor nanoparticle composition or at least one cyclic Group IVA compound to form a thin film, (ii) coating the thin film with the other, and (iii) curing the coated thin film to form a semiconducting thin film. The semiconducting thin film includes a sintered mixture of semiconductor nanoparticles in hydrogenated, at least partially amorphous silicon and/or germanium. The thin film exhibits improved conductivity, density, adhesion and/or carrier mobility relative to an otherwise identical structure made by an identical process, but without either the semiconductor nanoparticles or the hydrogenated Group IVA element polymer. The present invention advantageously provides semiconducting thin film structures having qualities suitable for use in electronics applications, such as display devices or RF ID tags, while enabling high-throughput printing processes that form such thin films in seconds or minutes, rather than hours or days as with conventional photolithographic processes.

1 . A method of making a semiconductor film, comprising:
 a) printing or coating a semiconductor precursor composition on a substrate, the semiconductor precursor composition comprising nanoparticles of a Group IVA element and a solvent, the nanoparticles having a passivation layer covalently bound thereto, the passivation layer selected from the group consisting of an alcohol, an alcoholate, a thiol, a thiolate, an alkyl group, an aralkyl group, and combinations thereof;   b) curing said semiconductor precursor composition to form said semiconductor film.   
     
     
         2 . The method of  claim 1 , wherein said passivated nanoparticles are present in said composition in a percentage by weight of from 0.1% to 49.95%. 
     
     
         3 . The method of  claim 1 , wherein said nanoparticles have an average particle diameter of less than 5 nm. 
     
     
         4 . The method of  claim 3 , wherein said nanoparticles have a particle size distribution of from 0.2 nm to less than 10 nm. 
     
     
         5 . The method of  claim 1 , wherein said solvent is aprotic. 
     
     
         6 . The method of  claim 5 , wherein said solvent has a boiling point of less than 250° C. at atmospheric pressure. 
     
     
         7 . The method of  claim 5 , wherein said solvent is selected from the group consisting of alkanes, alkenes, halogenated alkanes, halogenated alkenes, arenes, substituted arenes, ethers, cyclic ethers, aliphatic esters, aliphatic amides, and aliphatic sulfoxides. 
     
     
         8 . The method of  claim 1 , wherein the composition further comprises one or more additives selected from the group consisting of a tension reducing agent, a surfactant, a thickening agent, and a binder. 
     
     
         9 . The method of  claim 1 , wherein the composition further comprises a compound of the formula (ZH u R 3-u ) k , where Z is selected from the group consisting of B, P and As, u is an integer of from 0 to 3, k is 1 or 2, and each R is independently alkyl, aryl, aralkyl, a halogen, A s H s R″ 2-s  or AH t R″ 3-t , where A in the formula is independently Si or Ge, s is 0 to 2, t is 0 to 3, and R″ is alkyl, aryl, aralkyl, a halogen, or AH 3 . 
     
     
         10 . The method of  claim 1 , where the passivation layer comprises an alkyl group. 
     
     
         11 . The method of  claim 10 , where the passivation layer comprises a C 4 -C 20,  branched or unbranched alkyl group. 
     
     
         12 . The method of  claim 1 , wherein curing comprises sintering said composition to form said semiconductor film. 
     
     
         13 . The method of  claim 1 , wherein curing comprises irradiating said composition to form said semiconductor film. 
     
     
         14 . The method of  claim 1 , wherein curing comprises drying said composition and heating said substrate to a temperature of 400° C. or more for a period of 10 seconds to 60 minutes. 
     
     
         15 . The method of  claim 1 , wherein said Group IVA element comprises silicon and/or germanium. 
     
     
         16 . The method of  claim 1 , wherein the method comprises coating the semiconductor precursor composition on the substrate by spin coating, dip coating, or spray coating a solution, emulsion or suspension of the semiconductor precursor composition on the substrate. 
     
     
         17 . The method of  claim 1 , wherein printing or coating comprises printing or coating a layer of said semiconductor precursor composition on said substrate, selectively irradiating portions of said layer, and removing either irradiated or non-irradiated portions of said layer to form a pattern. 
     
     
         18 . The method of  claim 1 , wherein the method comprises printing the semiconductor precursor composition on the substrate by inkjet printing, screen printing, gravure printing, or flexographic printing the semiconductor precursor composition in said solvent onto said substrate. 
     
     
         19 . The method of  claim 18 , wherein the semiconductor precursor is printed in a pattern comprising a two-dimensional array of lines having a width of from 100 nm to 100 μm. 
     
     
         20 . The method of  claim 19 , wherein said lines have an inter-line spacing of from 100 nm to 100 μm and a thickness of from 0.01 μm to 1000 μm.