Thin-layer field-effect transistors with MIS structure whose insulator and semiconductor are made of organic materials

Claim 2

A thin-layer field-effect transistor (TFT) with an MIS structure comprising a thin semiconductor layer between a source and a drain, said thin semiconductor layer being in contact with one surface of a thin layer made of insulating material, and said thin insulating layer being in contact by its other surface with a conducting grid, wherein said semiconductor is composed of at least one polyconjugated organic compound which contains at least 8 conjugated bonds and has a molecular weight of no greater than approximately 2,000, and wherein said thin layer of insulating material comprises an insulating organic polymer having a dielectric constant at least equal to 5.

Claim 3

A transistor according to claim 1, wherein said insulating polymer has a dielectric constant of at least 6.

Claim 4

A transistor according to claim 1, wherein said insulating polymer is polyvinyl alcohol.

Claim 5

A transistor according to claim 1, wherein said insulating polymer is cyanoethylpullulane.

Claim 6

A transistor according to claim 1, wherein said polyconjugated organic compound has at least 10 conjugated bonds.

Claim 7

A transistor according to claim 1, wherein said polyconjugated organic compound contains a sufficient number of conjugated bonds for its mobility under a field effect to be at least equal to 10 -3 cm 2 V -1 s -1 .

Claim 8

A transistor according to claim 1, wherein said polyconjugated organic compound is at least one member selected from the of: conjugated oligomers whose units include or are constituted by phenylene groups that may be substituted, ortho-fused or ortho- and peri-fused aromatic polycyclic hydrocarbons having 4 to 20 fused rings, polyenes with the formula H--C(T.sub.1)=C(T.sub.2).sub.r --H wherein T 1 and T 2 independently represent --H or a lower alkyl and r is a whole number which may range from 8 to 50, and conjugated oligomers whose repeating units contain at least one five-link heterocycle.

Claim 9

A transistor according to claim 7, wherein said oligomers containing phenylene units are represented by formula I: ##STR4## wherein R" 1 , R" 2 , and Z 1 each independently represent --H, Cl, F or a trifluoromethyl group or a nitro group, Y' represents --C( T 1 )=C(T 2 )-- --C.tbd.C-- --N(R')-- --N═N-- --C(R')=N-- --N═C(R')--, T 1 and T 2 independently represent --H or a lower alkyl, R' represents --H, alkyl, substituted alkyl, aryl, or substituted aryl, n' is a number equal to zero or 1, n' is a number equal to zero or 1, and n is a whole number that may range between 3 and 12.

Claim 10

A transistor according to the claim 8, wherein Z 1 represents --H.

Claim 11

A transistor according to claim 7, wherein said aromatic polycyclic compound is an ortho-fused or ortho- and peri-fused polycyclic compound represented by formula II: ##STR5## corresponding to the molecular formula: C.sub.4t+10 H.sub.2t+8 t being a whole number which can range from 2 to 15.

Claim 12

A transistor according to 8, wherein said aromatic heterocycle oligomer is an oligomer with formula: ##STR6## wherein: X and X' represent independently O, S, Se, Te, or --N(R)--, R represents H, alkyl, substituted alkyl, aryl, or substituted aryl; R 1 , R 2 , R' 1 , R' 2 , R' 3 , and R" 3 each independently represent --H, Cl, F, --CF 3 , --NO 2 , --CN, --COOR 3 , --N(R 4 ) (R 5 ) , alkyl, substituted alkyl, aryl, substituted aryl, alkoxy or polyalkoxy, R 3 represents an alkyl or substituted alkyl group or a metal, R 4 represents H or an alkyl or substituted alkyl group, R 5 represents an alkyl, acyl, or aryl group, or at least one of the pairs R 1 and R 2 and R' 1 and R' 2 together represent a divalent hydrocarbon group which may be unsaturated, interrupted, terminated or a combination thereof by at least one heteroatom, Y, Y 1 , Y 2 , and Y 3 independently represent the following groups: --C(R')=C(R")-- --C.tbd.C-- --N(R')-- --N═N-- --C(R')═N----N═C(R')--, R' and R" independently represent --H, alkyl, substituted alkyl, aryl, or substituted aryl, a, b, a', b' are numbers equal to 0 or 1, or Y 1 may also represent a cyclic or heterocyclic arylene group, and in this case b=1 and a'=0, s and t are whole numbers, including zero, of which at least one is different from zero, m' is a whole number equal to at least 1, the numbers s, t, and m' are such that m' (s+t)=m, m being a whole number between 4 and 24.

Claim 13

A transistor according to 8, wherein said aromatic heterocycle oligomer is an oligomer with formula: ##STR6## wherein: X and X' represent independently O, S, Se, Te, or --N(R)--, R represents H, alkyl, substituted alkyl, aryl, or substituted aryl; R 1 , R 2 , R' 1 , R' 2 , R' 3 , and R" 3 each independently represent --H, Cl, F, --CF 3 , --NO 2 , --CN, --COOR 3 , --N(R 4 ) (R 5 ) , alkyl, substituted alkyl, aryl, substituted aryl, alkoxy or polyalkoxy, R 3 represents an alkyl or substituted alkyl group or a metal, R 4 represents H or an alkyl or substituted alkyl group, R 5 represents an alkyl, acyl, or aryl group, or at least one of the pairs R 1 and R 2 and R' 1 and R' 2 together represent a divalent hydrocarbon group which may be unsaturated, interrupted, terminated or a combination thereof by at least one heteroatom, Y, Y 1 , Y 2 , and Y 3 independently represent the following groups: --C(R')=C(R")-- --C.tbd.C-- --N(R')-- --N═N-- --C(R')═N----N═C(R')--, R' and R" independently represent --H, alkyl, substituted alkyl, aryl, or substituted aryl, a, b, a', b' are numbers equal to 0 or 1, or Y 1 may also represent a cyclic or heterocyclic arylene group, and in this case b=1 and a'=0, s and t are whole numbers, including zero, of which at least one is different from zero, m' is a whole number equal to at least 1, the numbers s, t, and m' are such that m' (s+t)=m, m being a whole number between 4 and 24.

Claim 14

A transistor according to claim 11, wherein at least one of R' 3 and R" 3 represents --H.

Claim 15

A switching or amplification element comprising a transistor as defined in claim 1.

Claim 16

A transistor according to claim 6, wherein said mobility is at least 10 -1 cm 2 V -1 s -1 .