Doped hydridosilane compositions, and method for producing same

Abstract

The present invention relates to compositions comprising at least one hydridosilane of the generic formula Si.sub.nH.sub.m with n5 and m=(2n) and (2n+2) and at least one compound of the formula H.sub.nB (OR).sub.3n with R=C.sub.1-C.sub.10-alkyl, C.sub.6-C.sub.10-aryl, C.sub.7-C.sub.14-aralkyl, halogen, n=0, 1, 2, to processes for preparation thereof and use thereof.

Claims

1. A composition comprising: (i) at least one hydridosilane of formula Si.sub.nH.sub.m with n5 and m=(2n) to (2n+2), and (ii) at least one compound of formula H.sub.nB(OR).sub.3n with R=C.sub.1-C.sub.10-alkyl, C.sub.6-C.sub.10-aryl, C.sub.7-C.sub.14-arylalkyl, or halogen, and n=0, 1, or 2.

2. The composition according to claim 1, wherein the at least one hydridosilane is a hydridosilane oligomer prepared from a hydridosilane of formula Si.sub.xH.sub.2x+2 with x3 or a cyclic hydridosilane of formula Si.sub.xH.sub.2x with x5.

3. The composition according to claim 2, wherein the hydridosilane oligomer is obtained via thermal oligomerization of a composition comprising, as hydridosilane, at least one hydridosilane of formula Si.sub.xH.sub.2x+2 with x3-20 in the absence of a catalyst at a temperature of less than 235 C.

4. The composition according to claim 3, wherein the hydridosilane of the formula Si.sub.xH.sub.2x+2 is neopentasilane.

5. The composition according to claim 2, wherein the hydridosilane of the formula Si.sub.xH.sub.2x with x5 is cyclopentasilane.

6. The composition according to claim 1, wherein the compound of the formula H.sub.nB(OR).sub.3n has a formula H.sub.nB(OC.sub.4H.sub.9).sub.3n with n=1 or 2.

7. The composition according to claim 1, further comprising at least one solvent.

8. The composition according to claim 3, further comprising a hydridosilane of formula Si.sub.nH.sub.2n+2 with n=5-9.

9. A process for preparing the composition according to claim 1, comprising mixing the at least one hydridosilane, the at least one compound of the formula H.sub.nB(OR).sub.3n and any further constituents.

Description

EXAMPLES

Example 1

(1) To 1 g of NPO (Mw2200 g/mol) was added 0.124 g of B(O-n-Bu).sub.3, and oligomerization was effected at 30 C. for 180 min. 0.1 g of the resulting p-doped NPO was formulated together with 0.069 g of cyclooctane and 0.161 g of toluene and the formulation was applied to a glass substrate. In a coating operation at 6000 rpm and a subsequent conversion operation at 500 C./60 s, it was possible to obtain a p-doped a-Si layer of 152 nm. The dark electrical conductivity is 210.sup.7 S/cm.

Example 2

(2) Diborane (10% in N.sub.2) was introduced into a mixture of 1 g of NPS and 0.035 g of THF, and oligomerization was effected at 30 C. over a period of 210 min. To 0.1 g of the resulting p-doped NPO were added 0.05 g of cyclooctane and 0.452 g of toluene. The resulting formulation was analysed by means of .sup.11B NMR spectroscopy, and B(O-n-Bu).sub.3 ( (.sup.11B)=19 ppm (s)), HB(O-n-Bu).sub.2 ((.sup.11B)=27 ppm (d, J.sub.BH=160 Hz)), and H.sub.2B(O-n-Bu) ((.sup.11B)=8 ppm (t, .sup.1J.sub.BH=124 Hz)) were observed. In addition, the formulation was applied to a glass substrate. In a coating operation at 2000 rpm and a subsequent conversion operation at 500 C./60 s, it was possible to obtain a p-doped a-Si layer of 60 nm. The dark electrical conductivity is 1.110.sup.3 S/cm.

Comparative Example

(3) To 5 g of NPS were added 2.587 g of B(Et).sub.3 (1 M in THF), and oligomerization was effected at 30 C. for 120 min. 0.1 g of the resulting p-doped NPO was formulated together with 0.05 g of cyclooctane and 0.45 g of toluene and the formulation was applied to a glass substrate. In a coating operation at 6000 rpm and a subsequent conversion operation at 500 C./60 s, it was possible to obtain a p-doped a-Si layer of 37 nm. The dark electrical conductivity is 210.sup.8 S/cm.

Experimental

(4) All studies were conducted in gloveboxes produced by M. Braun lnertgas-Systeme GmbH or by means of standard Schlenk methodology (D. F. Shriver, M. A. Drezdzon, The manipulation of air sensitive compounds, 1986, Wiley VCH, New York, USA) under an inert atmosphere of dry nitrogen (N.sub.2; O.sub.2 content: <10 ppm; H.sub.2O content: <10 ppm). Dry oxygen-free solvents (cyclooctane, toluene) were prepared by means of a solvent drying system of the MB-SPS-800-Auto type, manufactured by M. Braun lnertgas-Systeme GmbH. Deuterated benzene (C.sub.6D.sub.6) was sourced from Sigma-Aldrich, Coorp. and was stored over molecular sieve (4 ) for at least 2 days prior to use for drying purposes. NMR spectra were measured on a spectrometer of the Varian INOVA 300 (.sup.11B: 96.2 MHz) type from Varian, Inc., at room temperature. Chemical shifts are reported in comparison to an external reference (BF.sub.3*Et.sub.2O). The formulations described were made up at room temperature and applied to the substrate (EagleXG glass from Corning Inc.) by means of a PE syringe (including syringe filter: 1 m). The wet films were produced with a Spincoat G3P-8 spin-coater from SCS Specialty Coating Systems, Inc. at 25 C. The conversion of the wet films was conducted on standard laboratory hotplates from HARRY GESTIGKEIT GmbH. Layer thicknesses were measured by means of a SENpro ellipsometer from SENTECH Gesellschaft fr Sensortechnik mbH with defined angles of incidence between 40 and 90 (5 steps). Contact connection with the layers produced was achieved by the application of silver contacts by means of a sputtering system of the Emscope model SC 500 type from Quorum Technologies Ltd. Measurements for determination of dark electrical conductivity were conducted on a two-point measuring system from Keithley Instruments Inc. in an N.sub.2 atmosphere and in the dark in a closed metal container at 25 C.