Silicon Polymers, Methods of Polymerizing Silicon Compounds, and Methods of Forming Thin Films from Such Silicon Polymers

• US 20080085373A1
• Filed: 10/04/2007
• Published: 04/10/2008
• Est. Priority Date: 10/06/2006
• Status: Active Grant

• Current Assignee: Ensurge Micropower ASA
• Original Assignee: Kovio Incorporated (Ensurge Micropower ASA)
• Inventors: Ridley, Brent, KARSHTEDT, Dmitry, Rockenberger, Joerg, Zurcher, Fabio, Scher, Erik
• Granted Patent: US 8,092,867 B2
• Time in Patent Office: Days
• US Class Current: 427/487
• CPC Class Codes: C08G 77/60 in which all the silicon atoms are connected by linkages other than oxygen atoms
• CPC Class Codes: C09D 183/16 in which all the silicon atoms are connected by linkages other than oxygen atoms
• CPC Class Codes: H01L 21/02282 liquid deposition, e.g. spin-coating, sol-gel techniques, spray coating
• CPC Class Codes: H01L 21/02628 using solutions
• CPC Class Codes: H01L 27/1214 comprising a plurality of TFTs formed on a non-semiconducting substrate, e.g. driving circuits for AMLCDs
• CPC Class Codes: H01L 27/1292 using liquid deposition, e.g. printing

Abstract

Compositions and methods for controlled polymerization and/or oligomerization of hydrosilanes compounds including those of the general formulae Si_nH_2n and Si_nH_2n+2 as well as alkyl- and arylsilanes, to produce soluble silicon polymers as a precursor to silicon films having low carbon content.

Claims

1. A composition comprising an oligosilane or polysilane of consisting essentially of (i) hydrogen and (ii) silicon and/or germanium, having a molecular weight of from 450 to about 2300 g/mol, which, after coating and/or printing the composition and forming a oligo- or polysilane film, then curing, forms an amorphous, hydrogenated semiconductor film having a carbon content of not greater than 0.1 at %.

2. The composition of claim 1, wherein the molecular weight is from about 500 to about 1500 g/mol.

3. The composition of claim 1, wherein at least 50 mol % of the composition consists of the oligosilane or polysilane.

4. The composition of claim 1, consisting essentially of hydrogen and silicon.

5. The composition of claim 1, wherein the film has an oxygen content of not greater than 0.1 at %.

6. A formulation, comprising:

a) the composition of claim 1;

and

b) a solvent in which the oligosilane or polysilane is soluble.

23. A method of forming a semiconductor film from the formulation of claim 6, comprising the steps of:

a) coating or printing said formulation onto a substrate;

b) heating said coated or printed formulation sufficiently to form an amorphous, hydrogenated semiconductor; and

c) optionally annealing and/or irradiating said amorphous, hydrogenated semiconductor sufficiently to at least partially crystallize and/or reduce a hydrogen content of said amorphous, hydrogenated semiconductor and form said semiconductor film.

24. A method of making a thin film transistor, capacitor, diode and/or resistor device and/or circuit, comprising making a semiconductor film therein by the method of claim 23, then forming a conductor thereon.

7. A composition comprising an oligosilane or polysilane of consisting essentially of (i) hydrogen and (ii) silicon and/or germanium, having a chain length from 10 to about 1,000,000 Si and/or Ge units, which, after coating and/or printing the composition (optionally with simultaneous or immediately subsequent UV irradiation) and forming a oligo- or polysilane film, then curing to form an amorphous, hydrogenated semiconductor film having a carbon content of not greater than 0.1 at %.

8. The composition of claim 7, wherein the chain length ranges from 15 to about 10,000 Si and/or Ge units.

9. The composition of claim 8, wherein the chain length ranges from 15 to about 150 Si and/or Ge units.

10. A formulation, comprising:

a) the composition of claim 7;

and

b) a solvent in which the oligosilane or polysilane is soluble.

11. A method of making an oligosilane or polysilane, comprising:

a) combining a silane compound of the formula A_nH_2n+2 and/or a cyclosilane compound of the formula c-A_mH_2m with a heterogeneous catalyst consisting essentially of an elemental Group 7-12 transition metal or a substrate-anchored derivative thereof to form the oligosilane or polysilane, where each instance of A is independently Si or Ge;

n is an integer of from 1 to 10; and

m is an integer of from 4 to 6; and

b) removing said catalyst from said oligosilane or polysilane.

12. The method of claim 11, wherein the Group 7-12 transition metal is selected from the group consisting of Rh, Fe, Ru, Os, Co, Ir, Ni, Pd, and Pt.

13. The method of claim 12, wherein the Group 7-12 transition metal is selected from the group consisting of Rh and Ru.

14. The method of claim 12, wherein the Group 7-12 transition metal is supported on a stationary phase.

15. The method of claim 14, wherein the stationary phase is selected from the group consisting of silica, alumina, silicates, aluminates, aluminosilicates and polymer beads.

16. The method of claim 11, wherein the catalyst is present in an amount of from 0.01 to 10 transition metal atoms to 100 A atoms.

17. The method of claim 11, wherein the silane compound has the formula A_nH_2n+2.

18. The method of claim 11, wherein removing said catalyst from said oligosilane or polysilane comprises filtering the combined catalyst and oligosilane or polysilane.

19. The method of claim 11, wherein excess silane compound is removed by applying a vacuum for a length of time sufficient to reduce the amount of silane compound in the reaction mixture to less than 10% by weight of all oligosilane(s), polysilane(s) and silanes in the reaction mixture.

20. A method of making a polysilane, comprising:

a) combining a silane compound of the formula A_aH<sub>2a+2−

b</sub>R_b and/or the formula c-A_mH_pmR¹_rm with an elemental metal catalyst or a catalyst of the formula R³_xR⁴_zR⁵_zMX_w (or a multinuclear or substrate-anchored derivative thereof) to form a polysilane of the formula H-[(A_aH<sub>2a−

b</sub>R_b)_n-(c-A_mH<sub>(pm−

2)</sub>R¹_rm)_q]-H, or a branched or cross-linked version thereof, where each instance of A is independently Si or Ge, 1≦

a≦

100, and each instance of R and R¹ is independently hydrogen, aryl or -A_cH<sub>2c+1−

d</sub>R²_d (where R² is aryl, alkyl or H, and c is an integer from 1 to

     4);

n*a≧

6 if q=0, q≧

2 if n=0, and (n+q)≧

2 if both n and q # 0;

m is an integer from 3 to 8, p=2−

r, and r is 0 or 1 or 2;

M is a metal selected from the group consisting of Rh, Fe, Ru, Os, Co, Ir, Ni, Pd, and Pt, each of x, y, z and w is an integer of from 0 to 5, and 3≦

(w+x+y+z)≧

6;

each instance of R³, R⁴ and R⁵ is independently a substituted or non-substituted cyclopentadienyl, indenyl, fluorenyl, allyl, benzyl, silyl, (per)alkylsilyl, germyl, (per)alkylgermyl, hydride, phosphine, amine, sulfide, carbon monoxide, nitrile, isonitrile, siloxyl, germoxyl, hydrocarbyl, hydrocarbyloxy, hydrocarbylphosphino, hydrocarbylamino, or hydrocarbylsulfido ligand, or two or more of R³, R⁴ and R⁵ together may be a polydentate phosphine, amine, oxo and/or carbido ligand; and

X is a halogen or a halogen-equivalent; and

b) removing said catalyst from said poly(aryl)silane.

21. The method of claim 20, wherein removing said catalyst from said poly(aryl)silane comprises contacting said polysilane with an adsorbent or adding a solvent in which said poly(aryl)silane is soluble and said catalyst is insoluble to precipitate the catalyst, then filtering the precipitated catalyst.

22. The method of claim 20, wherein the silane compound has the formula AH_aR₄₋

a.

25. A thin film transistor, capacitor, diode, resistor device, circuit, RFID tag, display backplane, sensor and/or photovoltaic device, comprising the semiconductor film made by the method of claim 20.