Organic semiconductor device having an active dielectric layer comprising silsesquioxanes
View Patent ↗An organic field effect transistor (FET) is described with an active dielectric layer comprising a low-temperature cured dielectric film of a liquid-deposited silsesquioxane precursor. The dielectric film comprises a silsesquioxane having a dielectric constant of greater than 2. The silsesquioxane dielectric film is advantageously prepared by curing oligomers having alkyl(methyl) and/or alkyl(methyl) pendant groups. The invention also embraces a process for making an organic FET comprising providing a substrate suitable for an organic FET; applying a liquid-phase solution of silsesquioxane precursors over the surface of the substrate; and curing the solution to form a silsesquioxane active dielectric layer. The organic FET thus produced has a high-dielectric, silsesquioxane film with a dielectric constant of greater than about 2, and advantageously, the substrate comprises an indium-tin oxide coated plastic substrate.
1. An organic field effect transistor (OFET), comprising:
a gate dielectric layer on a substrate, said gate dielectric layer comprising at least one silsesquioxane precursor oligomer having phenyl pendant groups, and wherein said substrate is coated with indium tin oxide.
2. The OFET recited in claim 1 , wherein said substrate comprises polyethylene terphthalate.
3. The OFET recited in claim 1 , further comprising:
a gate electrode on said substrate, wherein said gate dielectric is on said gate electrode;
an organic semiconducting layer on said gate dielectric layer; and
a source electrode and a drain electrode in contact with said organic semiconducting layer.
4. The OFET recited in claim 3 , wherein said substrate comprises polyethylene terphthalate.
5. The OFET recited in claim 1 , further including another silsesquioxane precursor oligomer having methyl pendant groups.
6. The OFET recited in claim 1 , further including another silsesquioxane precursor oligomer having dimethyl pendant groups.
7. The OFET recited in claim 1 , wherein said silsesquioxane precursor oligomer is an alkyl(methyl)phenyl oligomer.
8. An organic field effect transistor (OFET), comprising:
a gate dielectric layer on a substrate, said gate dielectric layer comprising at least one silsesquioxane precursor oligomer having phenyl pendant groups and wherein said gate dielectric layer is a silane-reagent treated layer.
9. The OFET recited in claim 8 , wherein said silane reagent is selected from the group X-Si(OR 1 ) m (R 2 ) n , where the values for m and n are from 0 to 3 and m+n=3; R 1 is an alkyl group having from 1 to 6 carbon atoms; R 2 is an alkyl group having from 1 to 16 carbon atoms or a halogen group; and X is a substituent selected from a substituted or unsubstituted aryl, F 3 C(F 2 C) 9 CH 2 —, the group NH(Si)(CH 3 ) 3 ; and a saturated or unsaturated alkyl or alkoxycarbonyl having from 6 to 20 carbon atoms.
10. The OFET recited in claim 9 , wherein said silane reagent is selected from F 3 C(F 2 C) 9 CH 2 —Si(OCH 3 ) 3 ; C 8 H 17 Si(OCH 3 )(CH 3 ) 2 ; C 6 H 5 Si(OCH 3 ) 3 ; C 18 H 37 Si(OCH 3 ) 3 ; CH 2 CH—C(O)—O—(CH 2 ) 3 Si(OCH 3 )(CH 3 ) 2 ; F 3 C(F 2 C) 9 —Si(CL) 3 ; Cl—CH 4 SiCl 2 CH 3 ; and (CH 3 ) 3 SiNHSi(CH 3 ) 3 .
11. The OFET of claim 8 , wherein said substrate is coated with indium tin oxide.
12. The OFET recited in claim 11 , wherein said substrate comprises polyethylene terphthalate.
13. The OFET recited in claim 8 , further comprising:
a gate electrode on said substrate, wherein said gate dielectric is on said gate electrode;
an organic semiconducting layer on said gate dielectric layer; and
a source electrode and a drain electrode in contact with said organic semiconducting layer.