Semiconductor layer, process for forming the same, and semiconductor light emitting device

Abstract

A semiconductor layer contains, as a principal constituent, a Group III-V semiconductor compound, which may be represented by the general formula: AlxGayInzN, wherein x represents a number satisfying the condition 0≦x<1, y represents a number satisfying the condition 0

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic plan view showing a film forming apparatus, which is appropriate for use in film formation of a semiconductor layer in accordance with the present invention,

FIG. 1B is a schematic side view showing the film forming apparatus of FIG. 1A,

FIG. 1C is a graph showing an example of a laser beam profile,

FIG. 2A is a sectional view showing a semiconductor laser, which acts as a first embodiment of the semiconductor light emitting device in accordance with the present invention,

FIG. 2B is an enlarged sectional view showing a semiconductor active layer constituting the semiconductor laser of FIG. 2A,

FIG. 3 is a sectional view showing a semiconductor laser, which acts as a second embodiment of the semiconductor light emitting device in accordance with the present invention,

FIG. 4A is a sectional view showing a light emitting diode, which acts as a third embodiment of the semiconductor light emitting device in accordance with the present invention,

FIG. 4B is a band diagram showing a base plate and principal layers constituting the light emitting diode of FIG. 4A,

FIG. 5A is a perspective view showing a light emitting diode, which acts as a fourth embodiment of the semiconductor light emitting device in accordance with the present invention,

FIG. 5B is a perspective view showing a semiconductor light emitting apparatus, which is provided with the light emitting diode of FIG. 5A, with a sealing resin being omitted for clearness,

FIG. 5C is a perspective view showing the semiconductor light emitting apparatus of FIG. 5B, with the sealing resin being illustrated, and

FIG. 6 is a sectional view taken on line X-X′ of FIG. 5A.

Claims

1. A semiconductor layer, containing, as a principal constituent, a Groups III-V semiconductor compound, which may be represented by the general formula: AlxGayInzN

2. A semiconductor layer as defined in claim 1 wherein metalorganic compounds are used as the Group-III raw materials, and ammonia is used as the Group-V raw material.

3. A semiconductor layer as defined in claim 1 wherein the semiconductor layer is formed on a ZnO base plate.

4. A semiconductor layer as defined in claim 3 wherein the semiconductor layer is formed at a film formation temperature of at most 800° C.

5. A process for forming a semiconductor layer, comprising the steps of: forming a semiconductor layer on a base plate by use of a laser assisted metalorganic vapor phase epitaxy technique, the semiconductor layer containing, as a principal constituent, a Groups III-V semiconductor compound, which may be represented by the general formula: AlxGayInzN

6. A process for forming a semiconductor layer as defined in claim 5 wherein a laser beam is irradiated to the base plate from at least one direction, such that the laser beam passes just above the base plate and in a direction approximately parallel with a base plate surface of the base plate, supply of film formation raw materials with respect to the base plate is performed, while the laser beam is being thus irradiated to the base plate, andthe semiconductor layer is thereby formed.

7. A process for forming a semiconductor layer as defined in claim 6 wherein the irradiation of the laser beam to the base plate is performed with a laser beam profile, such that a distribution of a laser beam intensity, which distribution is taken in the direction parallel with the base plate surface, is approximately uniform, and such that the distribution of the laser beam intensity, which distribution is taken in the direction normal to the base plate surface, is the distribution approximately represented by the Gaussian distribution, and the laser beam is irradiated to the base plate, such that a peak of the distribution of the laser beam intensity, which distribution is taken in the direction normal to the base plate surface, is present within the range of at most 2 mm from the base plate surface, which range is taken in the direction normal to the base plate surface.

8. A semiconductor light emitting device, comprising a semiconductor layer as defined in claim 1.

9. A semiconductor light emitting device, comprising: i) a first electrical conduction type semiconductor base plate,ii) a first electrical conduction type electrode,iii) a first electrical conduction type cladding layer,iv) a semiconductor active layer,v) a second electrical conduction type cladding layer, andvi) a second electrical conduction type electrode,the first electrical conduction type semiconductor base plate being a ZnO base plate,each of the first electrical conduction type cladding layer and the second electrical conduction type cladding layer being an AlGaInN layer,the semiconductor active layer being a multiple quantum well active layer, which is constituted of a laminate structure comprising GaInN quantum well layers and at least one barrier layer selected from the group consisting of a GaInN barrier layer and an AlGaInN barrier layer,each of the first electrical conduction type cladding layer, the semiconductor active layer, and the second electrical conduction type cladding layer being formed by use of a laser assisted metalorganic vapor phase epitaxy technique.

10. A semiconductor light emitting device as defined in claim 9 wherein the first electrical conduction type semiconductor base plate is a ZnO (0001) base plate, and the first electrical conduction type cladding layer and the second electrical conduction type cladding layer are approximately lattice matched with the first electrical conduction type semiconductor base plate.

11. A semiconductor light emitting device as defined in claim 10 wherein a lattice constant of each of the GaInN quantum well layers constituting the semiconductor active layer is larger than the lattice constant of the first electrical conduction type semiconductor base plate, and the at least one barrier layer constituting the semiconductor active layer, which barrier layer is selected from the group consisting of the GaInN barrier layer and the AlGaInN barrier layer, is approximately lattice matched with the first electrical conduction type semiconductor base plate.

12. A semiconductor light emitting device as defined in claim 9 wherein the first electrical conduction type semiconductor base plate is an electrically conductive ZnO base plate and acts also as the first electrical conduction type electrode.

13. A semiconductor light emitting device as defined in claim 9 wherein the semiconductor light emitting device is a semiconductor laser, which is capable of producing a laser beam having a wavelength falling within the range of 480 nm to 630 nm.

14. A semiconductor light emitting device as defined in claim 9 wherein the semiconductor light emitting device is a light emitting diode, which has a constitution such that the plurality of the GaInN quantum well layers constituting the semiconductor active layer vary in transition wavelength from one another.

15. A semiconductor light emitting device as defined in claim 14 wherein the transition wavelengths of the plurality of the GaInN quantum well layers constituting the semiconductor active layer are set such that the transition wavelength of the GaInN quantum well layer, which is located closest to the first electrical conduction type semiconductor base plate, is the shortest, and the transition wavelengths of the GaInN quantum well layers are set to be long successively as the positions of the GaInN quantum well layers become remote from the base plate.

16. A semiconductor light emitting device as defined in claim 14 wherein the plurality of the GaInN quantum well layers constituting the semiconductor active layer have different compositions and/or different thicknesses.

17. A semiconductor light emitting device as defined in claim 14 wherein the first electrical conduction type electrode is formed in a pattern provided with an aperture, and light is taken out via the aperture to the exterior.

18. A semiconductor light emitting device as defined in claim 14 wherein the semiconductor light emitting device is a light emitting diode, in which white light is directly emitted from the semiconductor active layer.

19. A semiconductor light emitting device as defined in claim 9 wherein the semiconductor light emitting device is a light emitting diode, which has a plurality of light emitting sections varying in center emission wavelength.

20. A semiconductor light emitting device as defined in claim 19 wherein the first electrical conduction type electrodes of the plurality of the light emitting sections are electrically isolated from one another, and/or the second electrical conduction type electrodes of the plurality of the light emitting sections are electrically isolated from one another.

21. A semiconductor light emitting apparatus, comprising: i) a semiconductor light emitting device as defined in claim 20, andii) a current control section for controlling an electric current flowing across each of the plurality of the light emitting sections of the semiconductor light emitting device,the semiconductor light emitting device and the current control section being integrated on a mounting base plate.