Thin film Schottky barrier device

• US 4,907,040 A
• Filed: 09/15/1987
• Issued: 03/06/1990
• Est. Priority Date: 09/17/1986
• Status: Expired due to Fees

• Current Assignee: Konishiroku Photo Industry Co., Ltd.
• Original Assignee: Konishiroku Photo Industry Co., Ltd.
• Inventors: Menjo, Hiroshi, Sato, Taxay, Watanabe, Hideo, Nishi, Shinichi, Kobayashi, Hiroshi
• Primary Examiner(s): James, Andrew J.
• Assistant Examiner(s): Jackson, Jr., Jerome
• Application Number:
  US07/096,520
• Time in Patent Office: 903 Days
• Field of Search: 357/2, 357/15, 357/4, 357/45, 350/336, 350/334
• US Class Current: 257/52
• CPC Class Codes: G02F 1/1365 in which the switching element is a two-electrode device G02F1/136277 takes precedence

Abstract

Disclosed are an active matrix element and a method of manufacturing the same, wherein two first electrode layers are formed on a substrate, semiconductor thin films are formed on regions including the two first electrode layers, respectively, a second electrode layer is formed on the semiconductor thin layers and constituting Schottky barriers between the semiconductor layers and the second electrode layer.

Claims

1. An active matrix element of a pair of thin-film diodes connected in series and back-to-back with each other, wherein said pair of thin-film diodes comprises two first electrode layers formed on a substrate and spaced apart from each other, semiconductor layers respectively formed on said first electrode layers, and a second electrode layer integrally formed on said semiconductor layers and constituting Schottky barriers with said semiconductor layers and said second electrode layer.

2. An element according to claim 1, wherein at least one of said first electrode layers is opaque.

3. An element according to claim 2, wherein said at least one of said first electrode layers comprises a material selected from the group consisting of chromium, nickel, Nichrome, aluminum, molybdenum, magnesium, and highly doped n-type amorphous silicon.

4. An element according to claim 1, wherein said at least one of said first electrode layers is transparent.

5. An element according to claim 4, wherein said at least one of said first electrode layers comprises a material selected from the group consisting of ITO, stannic oxide, and zinc oxide.

6. An element according to claim 1, wherein a thickness of said first electrode layer falls within a range of 500Å

to 1 μ

m.

7. An element according to claim 1, wherein at least one of said semiconductor layers comprises a material selected from the group consisting of undoped amorphous silicon, phosphorus- or arsenic-doped amorphous silicon, fluorinated amorphous silicon, polysilicon, amorphous silicon carbide, amorphous silicon nitride, amorphous silicon germanium, tellurium, and selenium.

8. An element according to claim 1, wherein a thickness of said semiconductor layer falls within a range of 500Å

to 2 μ

m.

9. An element according to claim 1, wherein said semiconductor layer comprises a plurality of layer portions having different conductivities determined such that the conductivity of a lower layer portion of said semiconductor layer on a first electrode side is lower than that of an upper layer portion of said semiconductor layer on a second electrode side.

10. An element according to claim 1, wherein said semiconductor layers have a conductivity gradient declining from an upper layer portion of said semiconductor layer on a second electrode layer side to a lower layer portion thereof on a first electrode layer side.

11. An element according to claim 9, wherein a material for forming a semiconductor layer having a low conductivity is a material selected from the group consisting of undoped amorphous silicon, polysilicon, fluorinated amorphous silicon, amorphous silicon germanium, amorphous silicon carbide, amorphous silicon nitride, and amorphous germanium carbide.

12. An element according to claim 9, wherein a material for forming a semiconductor layer having a high conductivity is a material selected from the group consisting of phosphorus- or arsenic-doped amorphous silicon, amorphous silicon germanium, tellurium, selenium, polysilicon, and microcrystal silicon.

13. An element according to claim 9, wherein a thickness of said layer portion having the low conductivity falls within a range of 500Å

to 1.9 μ

m.

14. An element according to claim 1, wherein said second electrode layer comprises a material selected from the group consisting of platinum, gold, palladium, tungsten, rhodium, titanium, molybdenum, iridium, chromium, nickel, and Nichrome.

15. An element according to claim 1, wherein a thickness of said second electrode layer falls within a range of 50 to 5,000Å

.

16. An element according to claim 1, wherein said at least one of said pair of first electrode layers serves as a scanning electrode layer, and the other one thereof serves as a pixel electrode lead layer having the same width as that of said scanning electrode layer, and said semiconductor layers and said second electrode cover said scanning electrode layer and said pixel electrode lead layer in a widthwise direction.

17. An element according to claim 1, wherein one of said first electrode layers is opaque and the other of said first electrode layers is transparent.

18. An element according to claim 3, wherein the thickness of said first electrode layer falls within a range of 500Å

to 2000Å

.

19. An element according to claim 17, wherein the thickness of said first electrode layer falls within a range of 500Å

to 2000Å

.

20. An active matrix element for use in a liquid crystal cell of a pair of thin-film diodes connected in series and back-to-back with each other, the liquid crystal cell including an upper substrate, a counter electrode layer disposed on said upper substrate, a pixel electrode layer disposed on said lower substrate opposed to said counter electrode, first and second alignment layers disposed on said upper and lower substrates, respectively, and a liquid crystal layer disposed between said first and second alignment layers, said active matrix element comprising:

two first electrode layers disposed on said lower substrate, said two first electrode layers being spaced from each other, one of said first electrode layers being in ohmic contact with said pixel electrode layer;

two semiconductor layers disposed on said two first electrode layers, said two semiconductor layers being spaced from each other; and

a second electrode layer disposed on said two semiconductor layers to form a Shottky barrier between said second electrode and said two semiconductor layers, said second electrode layer being continuous.

21. An active matrix element for use in a liquid crystal cell of a pair of thin-film diodes connected in series and back-to-back with each other, the liquid crystal cell including an upper substrate, a lower substrate spaced from and parallel to the upper substrate, a pixel electrode layer disposed on the lower substrate opposed to the counter electrode, first and second alignment layers disposed on the upper and lower substrates, respectively, and a liquid crystal layer disposed between the first and second alignment layers, the active matrix element comprising:

two first electrode layers disposed on said lower substrate, said two first electrode layers being spaced from each other, one of said two first electrode layers being formed integrally with each pixel electrode layer;

two semiconductor layers disposed on said two first electrode layers, said two semiconductor layers being spaced from each other; and

a second electrode layer disposed on said two semiconductor layers to form a Shottky barrier between said second electrode and said two semiconductor layers, said second electrode layer being continuous.

22. An active matrix element for use in a liquid crystal cell of a pair of thin-film diodes connected in series and back-to-back with each other, the liquid crystal cell including an upper substrate, a lower substrate spaced from and parallel to the upper substrate, a counter electrode layer disposed on the upper substrate, a pixel electrode layer disposed on the lower substrate opposed to the counter electrode, first and second alignment layers disposed on the upper and lower substrates, respectively, and a liquid crystal layer disposed between the first and second alignment layers, the active matrix element comprising;

two first electrode layers disposed on said lower substrate, said two first electrode layers being spaced from each other, one of said two first electrode layers being formed integrally with each pixel electrode layer;

a continuous semiconductor layer disposed on said two first electrode; and

a second electrode layer disposed on said semiconductor layer to form a Shottky barrier between said second electrode and said continuous semiconductor layer, said second electrode layer being continuous.

23. An active matrix element as claimed in claim 22, wherein said pixel electrode layer includes an ear extending therefrom, said one of said two first electrode layers being formed integrally with said ear extending from said pixel electrode layer.

29. An active matrix element as claimed in claims 22, 24, 25, 26, or 28, wherein said continuous semiconductor layer includes a lower layer portion adjacent said first electrode layers and an upper layer portion disposed on said lower layer portion, said lower layer portion comprised of a material of a low conductivity and said upper layer portion comprised of a material of a high conductivity.

24. An active matrix element for use in a liquid crystal cell of a pair of thin-film diodes connected in series and back-to-back with each other, the liquid crystal cell including an upper substrate, a lower substrate spaced from and parallel to the upper substrate, a counter electrode layer disposed on the upper substrate, a pixel electrode layer disposed on the lower substrate opposed to the counter electrode, first and second alignment layers disposed on the upper and lower substrates, respectively, and a liquid crystal layer disposed between the first and second alignment layers, the active matrix element comprising:

two first electrode layers disposed on said lower substrate, said two first electrode layers being spaced from each other, one of said two first electrode layers being in ohmic contact with said pixel electrode layer, each of said two first electrode layers including a lower layer portion adjacent said substrate and an upper layer portion disposed on said lower layer portion;

a continuous semiconductor layer disposed on said two first electrode layer; and

a second electrode layer disposed on said semiconductor layer to from a Shottky barrier between said second electrode and said continuous semiconductor layers, said second electrode layer being continuous.

25. An active matrix element for use in a liquid crystal cell of a pair of thin-film diodes connected in series and back-to-back with each, the liquid crystal cell including an upper substrate, a lower substrate spaced from and parallel to the upper substrate, a counter electrode layer disposed on the upper substrate, a pixel electrode layer disposed on the lower substrate opposed to the counter electrode, first and second alignment layers disposed on the upper and lower substrates, respectively, and a liquid crystal layer disposed between the first and second alignment layers, the active matrix element comprising:

two first electrode layers disposed on said lower substrate, said first electrode layers being spaced from each other, each of said two first electrode layers including an upper layer portion, an intermediate layer portion and a lower layer portion said upper layer portion including an opaque layer of highly doped n-type amorphous silicon, said intermediate layer portion including chromium opaque layers and said lower layer portions including an inidium-tin oxide transparent material, one of said lower layer portions of said two first electrode layers being formed integral with said pixel electrode layer;

a continuous semiconductor disposed on said two first electrode layers; and

a second electrode layer disposed on said semiconductor layers to from a Shottky barrier between said second electrode layer and said continuous semiconductor layer, said second electrode layer being continuous.

26. An active matrix element for use in a liquid crystal cell of a pair of thin-film diodes connected in series and back-to-back with each other, the liquid crystal cell including an upper substrate, a lower substrate spaced from and parallel to the upper substrate, a counter electrode layer disposed on the upper substrate, a pixel electrode layer disposed on the lower substrate opposed to the counter electrode, first and second alignment layers disposed on the upper and lower substrates, respectively, and a liquid crystal layer disposed between the first and second alignment layers, the active matrix element comprising:

a scanning electrode lead layer disposed on said substrate;

a pixel electrode lead layer disposed on said substrate and spaced from said scanning electrode lead layer, said pixel electrode lead layer being formed integrally with said pixel electrode;

a first metal layer formed on said scanning electrode lead layer;

a second metal layer formed on said pixel electrode lead layer;

a continuous semiconductor layer formed on said scanning electrode lead layer and said pixel electrode lead layer; and

a second electrode layer formed on said semiconductor layer to form a Shottky barrier between said second electrode layer and said continuous semiconductor layer, said second electrode layer being continuous.

27. An active matrix element for use in a liquid crystal cell of a pair of thin-film diodes connected in series and back-to-back with each other, the liquid crystal cell including an upper substrate, a lower substrate spaced from and parallel to the upper substrate, a counter electrode layer disposed on the upper substrate, a pixel electrode layer disposed on the lower substrate opposed to the counter electrode, first and second alignment layers disposed on the upper and lower substrates, respectively, and a liquid crystal layer disposed between the first and second alignment layers, the active matrix element comprising:

a scanning electrode lead layer disposed on said substrate;

a pixel electrode lead layer disposed on said substrate and spaced from said scanning electrode lead layer, said pixel electrode lead layer being formed integrally with said pixel electrode;

a continuous semiconductor layer for encapsulating said scanning electrode lead layer and said pixel electrode lead layer; and

a second electrode layer formed on said semiconductor layer to form a Shottky barrier between said second electrode layer and said continuous semiconductor layer, said second electrode layer being continuous.

28. An active matrix element for use in a liquid crystal cell of a pair of thin-film diodes connected in series and back-to-back with each other, the liquid crystal cell including an upper substrate, a lower substrate spaced from and parallel to the upper substrate, a counter electrode layer disposed on the upper substrate, a pixel electrode layer disposed on the lower substrate opposed to the counter electrode, first and second alignment layers disposed on the upper and lower substrates, respectively, and a liquid crystal layer disposed between the first and second alignment layers, the active matrix element comprising:

two first electrode layers disposed on said lower substrate, said two first electrode layers being spaced from each other, one of said two first electrode layers being in ohmic contact with said pixel electrode layer;

a continuous semiconductor layer disposed on said two first electrode layers; and

a second electrode layer disposed on said continuous semiconductor layer to form a Shottky barrier between said second electrode and said continuous semiconductor layer, said second electrode layer being continuous.