Method of fabricating display with semiconductor circuits on monolithic structure and flat panel display produced thereby

• US 4,409,724 A
• Filed: 11/03/1980
• Issued: 10/18/1983
• Est. Priority Date: 11/03/1980
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Lam, Hon W., Tasch, Aloysious F. Jr., Penz, Perry A., Pankratz, John M.
• Primary Examiner(s): Ozaki, G.
• Application Number:
  US06/202,899
• Time in Patent Office: 1,079 Days
• Field of Search: 29/571, 29/576 B, 29/569 L, 29/577 C, 148/1.5, 148/187, 148/174, 148/175, 357/41
• US Class Current: 438/30
• CPC Class Codes: G02F 1/13454 Drivers integrated on the active matrix substrate G02F1/136277 takes precedence
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: H01L 21/268 using electromagnetic radiation, e.g. laser radiation
• 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 27/127 with a particular formation, treatment or patterning of the active layer specially adapted to the circuit arrangement
• CPC Class Codes: H01L 27/1274 using crystallisation of amorphous semiconductor or recrystallisation of crystalline semiconductor
• CPC Class Codes: Y10S 148/091 Laser beam processing of fets
• CPC Class Codes: Y10S 148/093 Laser beam treatment in general

Abstract

Method of fabricating a display with silicon integrated circuits included on the same monolithic structure and the flat panel display produced thereby. The display which may be of the liquid crystal or electrochromic type, for example, is formed as an x-y matrix display having individual address transistors respectively asociated with each of the display units or pixels. The substrate is preferably of transparent material, such as quartz or a glass plate, on which a polysilicon layer is disposed. The polysilicon layer is patterned to provide a plurality of islands which are subjected to a laser annealing treatment at an intensity sufficient to cause recrystallization thereof. The polysilicon material in the islands is converted by the laser annealing to crystalline silicon having an enhanced electron mobility characteristic such that a matrix array of address transistors in the form of MOSFETS can be fabricated in the individual islands. Thereafter, elements of the display are formed in conjunction with the matrix array of address transistors, beginning with the formation of an array of metal electrodes in respective association with corresponding address transistors. Various peripheral circuits for the display, such as drive circuits, are formed in other islands of crystalline silicon resulting from the laser annealing of the polysilicon islands such that a monolithic structure including a display with silicon integrated circuits for operating the display is produced.

Claims

1. A process of fabricating a semiconductor structure comprising:

forming a plurality of islands of polycrystalline semiconductor material disposed in spaced relation to each other on a substrate;

subjecting said polycrystalline semiconductor islands to focused energy from a source thereof wherein the focused energy is at an intensity sufficient to cause recrystallization of the polycrystalline semiconductor material of said islands;

converting the polycrystalline semiconductor material in said islands to crystalline semiconductor material having an enhanced electron mobility characteristic in response to the focused energy impinging thereon causing recrystallization thereof;

removing any regions untreated by focused energy and focused energy-induced distorted regions from each of said islands of crystalline semiconductor material; and

fabricating electronic devices in respective crystalline semiconductor islands.

2. A process of fabricating a semiconductor structure as set forth in claim 1, wherein the formation of said plurality of islands of polycrystalline semiconductor material on said substrate is accomplished by depositing a layer of polycrystalline semiconductor material on said substrate;

and

patterning said polycrystalline semiconductor layer to define said plurality of islands of polycrystalline semiconductor material disposed in spaced relation to each other on said substrate.

3. A process of fabricating a semiconductor structure as set forth in claim 1, wherein the focused energy to which said polycrystalline semiconductor islands are subjected is laser energy from a laser source maintained at an intensity sufficient to cause laser annealing and recrystallization of the polycrystalline semiconductor material in said islands.

4. A process of fabricating a semiconductor structure as set forth in claim 1, wherein the focused energy to which said polycrystalline semiconductor islands are subjected is energy from an electron beam maintained at an intensity sufficient to cause annealing and recrystallization of the polycrystalline semiconductor material in said islands.

5. A process of fabricating a semiconductor structure as set forth in claim 1, wherein the polycrystalline semiconductor material of said plurality of islands is polysilicon material.

6. The process of claim 1, wherein said substrate is transparent.

7. The process of claim 1, wherein said substrate comprises quartz.

8. A process of fabricating a semiconductor structure comprising:

depositing a layer of polycrystalline semiconductor on a substrate;

patterning said polycrystalline semiconductor layer to define a plurality of elongated islands of polycrystalline semiconductor material disposed in spaced parallel relation to each other on said substrate;

successively scanning each of said plurality of elongated islands of polycrystalline semiconductor material with a laser beam maintained at an intensity sufficient to cause annealing and recrystallization of each elongated island of polycrystalline semiconductor material;

converting the polycrystalline semiconductor material in each of said elongated islands to crystalline semiconductor material having an enhanced electron mobility characteristic in response to the scanning of the laser beam causing annealing and recrystallization thereof;

removing any unannealed regions and laser-induced distorted regions from each of said elongated islands of crystalline semiconductor material;

further patterning said elongated islands of crystalline semiconductor material to sub-divide each of said elongated islands into a plurality of smaller islands of crystalline semiconductor material disposed in spaced relation to each other on said substrate; and

thereafter fabricating electronic devices in respective smaller islands of crystalline semiconductor material.

9. A process of fabricating a semiconductor structure as set forth in claim 8, wherein the step of further patterning said elongated islands of crystalline semiconductor material to sub-divide said elongated islands is responsible for removing any unannealed regions and laser-induced distorted regions from each of said elongated islands of crystalline semiconductor material which occurs simultaneously therewith.

10. The process of claim 8, wherein said substrate is transparent.

11. The process of claim 8, wherein said substrate comprises quartz.

12. A process of fabricating a monolithic display structure combined with semiconductor integrated circuits on the same substrate comprising:

forming a plurality of islands of polycrystalline semiconductor material disposed in spaced relation to each other on a substrate;

subjecting said polycrystalline semiconductor islands to focused energy from a source thereof maintained at an intensity sufficient to cause recrystallization of the polycrystalline semiconductor material of said islands;

converting the polycrystalline semiconductor material in said islands to crystalline semiconductor material having an enhanced electron mobility characteristic in response to the impingement of the focused energy thereon causing recrystallization thereof;

removing any untreated regions and focused energyinduced distorted regions from each of said islands of crystalline semiconductor material;

fabricating electronic devices in respective crystalline semiconductor islands; and

forming an electronically operable display on the same side of said substrate as said electronic devices including respective display units electrically interconnected with a corresponding one of said electronic devices.

13. A process of fabricating a monolithic display structure as set forth in claim 12, wherein the formation of said plurality of islands of polycrystalline semiconductor material on said substrate is accomplished by depositing a layer of polycrystalline semiconductor material on said substrate;

and

patterning said polycrystalline semiconductor layer to define said plurality of islands of polycrystalline semiconductor material disposed in spaced relation to each other on said substrate.

14. A process of fabricating a monolithic display structure as set forth in claim 13, further including etching a relief grating in the surface of said substrate prior to the deposition of the layer of polycrystalline semiconductor material on the said surface of said substrate.

15. A process of fabricating a monolithic display structure as set forth in claim 12, wherein the focused energy to which said polycrystalline semiconductor islands are subjected is energy from an electron beam maintained at an intensity sufficient to cause annealing and recrystallization of the polycrystalline semiconductor material in said islands.

16. A process of fabricating a monolithic display structure as set forth in claim 12, wherein the focused energy to which said polycrystalline semiconductor islands are subjected is laser energy from a laser source maintained at an intensity sufficient to cause laser annealing and recrystallization of the polycrystalline semiconductor material in said islands.

17. A process of fabricating a monolithic display structure as set forth in claim 16, wherein said display units are formed as an array of display pixels arranged in rows and columns with each display pixel being electrically interconnected with one of said electronic devices.

18. A process of fabricating a monolithic display structure as set forth in claim 17, wherein said electronic devices are fabricated as metal-oxide-semiconductor field effect transistors in said crystalline semiconductor islands.

19. A process of fabricating a monolithic display structure as set forth in claim 18, wherein the polycrystalline semiconductor material of said plurality of islands is polysilicon material.

20. A process of fabricating a monolithic display structure as set forth in claim 19, wherein the display which is formed is a liquid crystal display.

21. The process of claim 12, wherein said substrate is transparent.

22. The process of claim 12, wherein said substrate comprises quartz.

23. A process of fabricating a monolithic display structure combined with semiconductor integrated circuits on the same substrate comprising:

depositing a layer of polycrystalline semiconductor material on a substrate;

patterning said polycrystalline semiconductor layer to define a plurality of elongated islands of polycrystalline semiconductor material disposed in spaced parallel relation to each other on said substrate;

successively scanning each of said plurality of elongated islands of polycrystalline semiconductor material with a laser beam maintained at an intensity sufficient to cause annealing and recrystallization of each elongated island of polycrystalline semiconductor material;

converting the polycrystalline semiconductor material in each of said elongated islands to crystalline semiconductor material having an enhanced electron mobility characteristic in response to the scanning of the laser beam causing annealing and recrystallization thereof;

removing any unannealed regions and laser-induced distorted regions from each of said elongated islands of crystalline semiconductor material;

further patterning said elongated islands of crystalline semiconductor material to sub-divide each of said elongated islands into a plurality of smaller islands of crystalline semiconductor material disposed in spaced relation to each other on said substrate;

fabricating electronic devices in respective smaller islands of crystalline semiconductor material; and

forming an electronically operable display on the same side of said substrate as said electronic devices including respective display units electrically interconnected with a corresponding one of said electronic devices.

24. A process of fabricating a monolithic display structure combined with semiconductor integrated circuits as set forth in claim 23, wherein the step of further patterning said elongated islands of crystalline semiconductor material to sub-divide said elongated islands is responsible for removing any unannealed regions and laser-induced distorted regions from each of said elongated islands of crystalline semiconductor material which occurs simultaneously therewith.

25. The process of claim 23, wherein said substrate is transparent.

26. The process of claim 23, wherein said substrate comprises quartz.