SEMICONDUCTOR LED, OPTO-ELECTRONIC INTEGRATED CIRCUITS (OEIC), AND METHOD OF FABRICATING OEIC

• US 20080197362A1
• Filed: 11/06/2007
• Published: 08/21/2008
• Est. Priority Date: 02/16/2007
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Kimura, Shinichiro, Saito, Shinichi, HISAMOTO, Digh
• Granted Patent: US 8,030,668 B2
• Time in Patent Office: Days
• US Class Current: 257/86
• CPC Class Codes: G02B 6/13 Integrated optical circuits characterised by the manufacturing method
• CPC Class Codes: G02B 6/43 Arrangements comprising a plurality of opto-electronic elements and associated optical interconnections
• CPC Class Codes: H01L 27/15 including semiconductor components having potential barriers, specially adapted for light emission
• CPC Class Codes: H01L 33/02 characterised by the semiconductor bodies
• CPC Class Codes: H01L 33/34 containing only elements of Group IV of the Periodic Table

Abstract

A light emitting diode demonstrating high luminescence efficiency and comprising a Group IV semiconductor such as silicon or germanium equivalent thereto as a basic component formed on a silicon substrate by a prior art silicon process, and a fabricating method of waveguide thereof are provided. The light emitting diode of the invention comprises a first electrode for implanting electrons, a second electrode for implanting holes, and a light emitting section electrically connected to the first and the second electrode, wherein the light emitting section is made out of single crystalline silicon and has a first surface and a second surface facing the first surface, wherein with respect to plane orientation (100) of the first and second surfaces, the light emitting section crossing at right angles to the first and second surfaces is made thinner, and wherein a material having a high refractive index is arranged around the thin film section.

Claims

1. A semiconductor LED, comprising:

an insulation layer formed on a semiconductor substrate; and

a first electrode for implanting electrons, a second electrode for implanting holes, and a light emitting section electrically connected to the first and the second electrode, each being formed on the insulation layer,

wherein the first electrode, the second electrode, and the light emitting section are respectively made of a first single crystalline material, and

wherein the light emitting section, which includes a light emitting element formed into a thin film with a film thickness being thinner than a film thickness of the insulation layer and being thin enough to emit light by the electron and hole implantations, and which is covered with a waveguide for transmitting light emitted by the light emitting element.

2. The semiconductor LED according to claim 1, wherein the light emitting section includes a plurality of light emitting elements covered with one waveguide.

3. The semiconductor LED according to claim 2, wherein the light emitting section includes a plurality of light emitting elements being sequentially arranged in a direction crossing the direction of a current flow therein.

4. The semiconductor LED according to claim 1, wherein a material for the thin film is a Group IV semiconductor.

5. The semiconductor LED according to claim 1, wherein a material for the thin film is an indirect transition type semiconductor.

6. The semiconductor LED according to claim 1, wherein the thin film has a thickness of 10 nm or less.

7. The semiconductor LED according to claim 4, wherein the Group IV semiconductor is silicon, of which surface has plane orientation (100) or a plane equivalent thereto.

8. The semiconductor LED according to claim 1, wherein the waveguide is formed of a silicon nitride film.

9. The semiconductor LED according to claim 8, wherein the waveguide is covered with a material having a refractive index relatively lower than that of a material composing the waveguide.

14. The semiconductor LED according to claim 1, wherein a surface of a semiconductor region not having the silicon oxide film formed thereon is coated with silicide, the compound of silicon and a metal.

15. The semiconductor LED according to claim 1, wherein a surface of a semiconductor region including the interface between the first semiconductor region and the second semiconductor region is covered by a silicon nitride film.

16. The semiconductor LED according to claim 1 further comprising:

a light receiving element formed on the semiconductor substrate; and

a waveguide for trapping light emitted by the light emitting element that connects the light emitting element with the light receiving element and guiding the light towards the light receiving element,

wherein the waveguide is composed of the silicon nitride film.

17. The semiconductor LED according to claim 1, wherein the waveguide composed of the silicon nitride film is formed on an upper portion of an interfacial area between the first semiconductor region and the second semiconductor region, the waveguide having a nearly semicircular cross section and having a nearly hemispherical shape at the end of the waveguide near the light emitting element and the light receiving element.

18. An opto-electronic integrated circuit, comprising:

a light emitting element described in claim 1; and

a MOSFET formed on a silicon thin film deposited on an insulation layer over a semiconductor substrate,

wherein the light emitting element and the MOSFET are connected by an optical wire or an electric wire.

19. An opto-electronic integrated circuit, comprising:

a light emitting element described in claim 1; and

a MOSFET formed over a semiconductor substrate,

wherein the light emitting element and the MOSFET are connected by an optical wire or an electric wire.

20. The opto-electronic integrated circuit according to claim 18, comprising:

a first silicon nitride film covering a luminous region of the light emitting element;

a second silicon nitride film covering a light receiving element that receives light emitted by the light emitting element; and

a third silicon nitride film composing a waveguide that connects the luminous region and the light receiving region.

21. The opto-electronic integrated circuit according to claim 20, wherein each of the first through the third silicon nitride films has a rectangle shaped cross section and a plurality of nitride films are formed as a side wall film on the side wall of the film.

22. The opto-electronic integrated circuit according to claim 20, wherein the first through the third silicon nitride films are waveguides, each having a nearly semicircular cross section.

23. The opto-electronic integrated circuit according to claim 22, wherein the waveguide has a refractive index greater than that of an interlayer insulation film covering the light emitting element and the light receiving element.

24. The opto-electronic integrated circuit according to claim 22, wherein the waveguide is prepared by heating a waveguide material processed into a rectangular shape and demonstrates fluidity to have a semicircular shaped cross section.

10. A semiconductor LED, comprising:

a semiconductor substrate provided with an insulation layer;

a single crystalline thin film formed on the insulation layer and having a first semiconductor region of a first conductive type and a second semiconductor region of a second conductive type opposite to the first conductive type; and

a light emitting element for emitting light by causing current to flow from one of the first and second semiconductor regions of the single crystalline thin film to the other,

wherein the second semiconductor region has a rectangle shape with one side being longer than the other and is surrounded by the first semiconductor region, and

wherein film thickness of the first and the second semiconductor region at and near an interface therebetween is thinner than film thickness of the first and the second semiconductor region except at the interface and except in an area near the interface.

11. The semiconductor LED according to claim 10, wherein a material for the first and the second semiconductor region is silicon.

12. The semiconductor LED according to claim 10, wherein a silicon oxide film is formed on the first and the second thin-film semiconductor region.

13. The semiconductor LED according to claim 10, wherein the first and the second thin-film semiconductor region has a film thickness of 10 nm or less.

25. A fabrication method of an opto-electronic integrated circuit, comprising the steps of:

boring a trench into a single crystalline silicon layer deposited on a first silicon oxide film over a semiconductor substrate until the trench reaches the first silicon oxide film;

filling the trench with a second silicon oxide film, and controlling a surface of the second silicon oxide film and a surface of the single crystalline silicon film to be almost same in height to form an oxide film;

forming, in a desired area of the single crystalline silicon film surrounded by the buried oxide film, a target light emitting element formation region in a manner that the first conductive type silicon region and the second conductive type silicon region are adjacent to each other;

forming the first conductive region in another desired area of the single crystalline silicon film surrounded by the buried oxide film;

forming the second conductive region in yet another desired area of the single crystalline silicon film surrounded by the buried oxide film;

depositing a silicon nitride film on a surface of the semiconductor substrate;

selectively removing the silicon nitride film near an interface between the first conductive type and the second conductive type in the target light emitting element formation region;

performing a selective oxidation process to grow a silicon oxide film on a surface of the silicon region from which the silicon nitride film is selectively removed;

removing the silicon oxide film used for the selective oxidation process;

growing an oxide film functioning as a gate oxide film of MOSFET on an exposed surface of the single crystalline silicon film;

depositing polycrystalline silicon functioning as a gate electrode of the MOSFET on the oxide film functioning as the gate oxide film to process a gate electrode pattern;

performing ion implantation on a region to be a diffusion layer of the MOSFET by using the gate electrode pattern as a mask, wherein a second conductive type impurity is implanted in the first conductive type single crystalline silicon film and a first conductive type impurity is implanted in the second conductive type single crystalline silicon film;

performing heat treatment on the semiconductor substrate to active the impurities being implanted;

forming a side wall insulation film on a side wall of the gate electrode;

depositing a metal on an exposed surface of the single crystalline silicon and heating, to form a silicate of the metal and silicon on the single crystalline silicon;

depositing an interlayer insulation film for covering elements including the MOSFET and planarizing the interlayer insulation film;

forming a waveguide on a luminous area of a light emitting element formed in the target light emitting element formation region;

depositing an interlayer insulation film for covering the waveguide and planarizing the interlayer insulation film; and

forming a wire for electrically interconnecting the light emitting element and elements including the MOSFET.