Integrated inorganic/organic complementary thin-film transistor circuit and a method for its production

• US 6,528,816 B1
• Filed: 05/29/2001
• Issued: 03/04/2003
• Est. Priority Date: 06/19/1998
• Status: Expired due to Term

• Current Assignee: Penn State Research Foundation (Pennsylvania State University)
• Original Assignee: Penn State Research Foundation (Pennsylvania State University)
• Inventors: Thomasson, Daniel B., Klauk, Hagen, Gundlach, David J., Jackson, Thomas, Bonse, Mathias
• Primary Examiner(s): Meier, Stephen D.
• Application Number:
  US09/485,847
• Time in Patent Office: 644 Days
• Field of Search: 257/40, 257/368, 438/99
• US Class Current: 257/40
• 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 29/66765 Lateral single gate single channel transistors with inverted structure, i.e. the channel layer is formed after the gate
• CPC Class Codes: H01L 29/78669 with inverted-type structure, e.g. with bottom gate
• CPC Class Codes: H01L 29/78684 having a semiconductor body comprising semiconductor materials of Group IV not being silicon, or alloys including an element of the group IV, e.g. Ge, SiN alloys, SiC alloys H01L29/7869 takes precedence
• CPC Class Codes: H10K 10/466 Lateral bottom-gate IGFETs comprising only a single gate
• CPC Class Codes: H10K 19/10 comprising field-effect transistors
• CPC Class Codes: H10K 19/20 comprising components having an active region that includes an inorganic semiconductor
• CPC Class Codes: H10K 85/113 Heteroaromatic compounds comprising sulfur or selene, e.g. polythiophene
• CPC Class Codes: H10K 85/615 Polycyclic condensed aromatic hydrocarbons, e.g. anthracene
• CPC Class Codes: H10K 85/655 comprising only sulfur as heteroatom

Abstract

An integrated organic/inorganic complementary thin-film transistor circuit comprises a first and a second transistor which are operatively connected on a common substrate, wherein the first transistor is an inorganic thin-film transistor and the second an organic thin-film transistor. The inorganic thin-film transistor is an n-channel transistor and the organic thin-film transistor is a p-channel transistor or vice versa. Each of the transistors has a separate gate electrode and the organic active semiconductor material is in the case of a p-channel semiconductor in the organic thin-film transistor electrically isolated from the inorganic thin-film transistor. In a first method for fabricating a transistor circuit of this kind separate gate electrodes are deposited for each transistor on a common substrate, the material for the source and the drain electrode of the organic thin-film transistor are deposited on the same layer level in the thin-film structure of the organic thin-film transistor and in each case the organic active semiconductor material in an organic p-channel transistor is provided electrically isolated from the inorganic n-channel transistor, and the organic active semiconductor material in an organic n-channel transistor optionally electrically isolated from the inorganic p-channel transistor.

Claims

1. An integrated inorganic/organic complementary thin-film transistor circuit comprising:

a first and a second transistor which are operatively connected and provided on a common substrate, wherein the first transistor is an inorganic thin-film transistor, and wherein the complementary thin-film transistor circuit forms a multilayer thin-film structure, wherein

the inorganic thin-film transistor is an n-channel transistor and the organic thin-film transistor is a p-channel transistor, or vice versa,

the organic active transistor material in each case being respectively a p-channel organic semiconductor material or an n-channel organic semiconductor material,

separate gate electrodes are provided for each of the transistors,

the organic active semicondutor in an organic p-channel transistor in each case is provided electrically isolated from the inorganic n-channel transistor, and

the organic active semiconductor in an organic n-channel transistor optionally is provided electrically isolated from the inorganic p-channel transistor.

2. A complementary thin-film transistor circuit according to claim 1, wherein the inorganic active semiconductor material is at least one of hydrogenated amorphous silicon (a-Si:

H), hydrogenated or unhydrogenated microcrystalline silicon (μ

c-Si;

H;

μ

c-Si), hydrogenated or unhydrogenated polycrystalline silicon (pc-Si;

H;

pc-Si), single crystal silicon, copper-doped polycrystalline germanium (pc-Ge;

Cu), cadmium selenide (CdSe), cadmium telluride (CdTe), and composite inorganic semiconductors based on said materials, possibly in single crystal form.

3. A complementary thin-film transistor circuit according to claim 2 wherein the inorganic transistor is an n-channel transistor, and wherein the inorganic active semiconductor material is hydrogenated amorphous silicon (a-Si:

H).

4. A complementary thin-film transistor circuit according to claim 2, wherein the inorganic transistor is a p-channel transistor, and wherein the inorganic active semiconductor material is a p-channel silicon material, particularly p-channel hydrogenated amorphous silicon (a-Si:

H).

5. A complementary thin-film transistor circuit according to claim 1, wherein the active semiconductor material in the organic thin-film transistor comprises at least one polyconjugated organic compound with a specific molecular weight.

6. A complementary thin-film transistor circuit according to claim 5, wherein the polyconjugated organic compound or compounds are at least one of conjugated oligomers, polycyclic aromatic hydrocarbons, particularly polyacenes, and polyenes.

7. A complementary thin-film transistor circuit according to claim 6, wherein the organic thin-film transistor is a p-channel transistor, wherein the organic semiconductor material is pentacene.

8. A complementary thin-film transistor circuit according to claim 1, wherein the organic thin-film transistor is an n-channel transistor, and wherein the organic active semiconductor material is copper hexadecafluorophtalocyanide (F₁₆CuPc).

9. A complementary thin-film transistor circuit according to claim 1, wherein the source electrode and the drain electrode of the organic thin-film transistor are provided in one and the same level in the thin-film structure of the organic thin-film transistor.

10. A method for fabricating an integrated inorganic/organic complementary thin-film transistor circuit comprising a first and a second transistor which are operatively connected and provided on a common substrate, wherein the first transistor is an inorganic thin-film transistor and the second transistor a organic thin-film transistor, and wherein the complementary thin-film transistor circuit forms a multilayer thin-film structure with successively deposited and patterned thin-film layers, the method comprising:

forming the inorganic thin-film transistor as an n-channel transistor and the organic thin-film transistor as a p-channel transistor by depositing respectively an n-channel inorganic active semiconductor material and a p-channel organic active semiconductor material or correspondingly forming the organic thin-film transistor as an n-channel transistor and the inorganic thin-film transistor as a p-channel transistor by depositing respectively an n-channel organic active semiconductor material and a p-channel inorganic active semiconductor material;

depositing separate gate electrodes for respectively the first and the second transistor on a common substrate;

depositing material for the source electrode and the drain electrode of the organic thin-film transistor on the same level in the thin-film structure of the organic thin-film transistor and in each case providing the organic active semiconductor material in an organic p-channel transistor electrically isolated from the inorganic n-channel transistor; and

optionally providing the organic active semiconductive material in an organic n-channel transistor electrically isolated from the inorganic p-channel transistor.

11. A method for fabricating an inorganic/organic complementary thin-film transistor circuit comprising a first and a second transistor which are operatively connected and provided on a common substrate, wherein the first transistor is an inorganic thin-film transistor and the second transistor an organic thin-film transistor, wherein the complementary thin-film transistor circuit forms a multilayer thin-film structure with successively deposited and patterned thin-film layers, and wherein the method comprises;

depositing separate gate electrodes of a first metal for each of the two transistors on a common substrate;

depositing separate inorganic isolators of silicon nitride (SiN_x) over each gate electrode;

depositing an inorganic active semiconductor in the form of hydrogenated amorphous silicon (a-Si;

H) above one of the gate electrodes which thus forms the gate electrode of the first transistor, depositing and patterning an n⁺ doped layer of either hydrogenated amorphous silicon (n⁺a-Si;

H) or hydrogenated microcrystalline silicon (n⁺ μ

c-Si;

H) or hydrogenated polycrystalline silicon (n⁺pc-Si;

H) as source and drain contacts for the first transistor;

depositing and patterning the source and drain electrodes of the first transistor in form of a second metal over the source and drain contacts thereof;

depositing and patterning the source and drain electrodes for the second transistor in the form of a third metal in the same layer level in the thin-film structure; and

forming an isolating double layer over the whole organic thin-film transistor and patterning this such that the source and drain electrodes and the gate isolator in the second transistor become exposed, whereafter a layer of pentacene is deposited above the isolating double layer and the exposed portion of the second transistor, the pentacene layer in the exposed portion forming the active semiconductor material of the organic thin-film transistor and being provided electrically isolated against the additional pentacene layer broken by a re-entrant edge of the profile of the isolating double layer.

12. A method according to claim 11, wherein the steps for forming the inorganic thin-film transistor are performed in a tri-layer process which forms an inverted staggered tri-layer structure.

13. A method according to claim 11, wherein the steps forming the inorganic thin-film transistor are performed in a back-channel etch process.

14. A method according to claim 11, further comprising:

isolating the active semiconductor in the form of pentacene in the organic thin-film transistor by a re-entrant profile of a broken double layer of polymethylmetacrylate (PMMA) and Novolac photoresist.

15. A method according to claim 11, further comprising:

evaporating gold thermally for forming the source and drain electrodes of the organic thin-film transistor.

16. A method according to claim 11, further comprising:

removing the pentacene layer which has been deposited over the isolating double layer.