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

Abstract

A semiconductor layer contains, as a principal constituent, a Groups III-V semiconductor compound, which may be represented by the general formula: BxAlyGazN, wherein x represents a number satisfying the condition 0

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph showing relationships between lattice constants and band gap energy of Groups III-V semiconductor compounds,

FIG. 2A 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. 2B is a schematic side view showing the film forming apparatus of FIG. 2A,

FIG. 2C is a graph showing an example of a laser beam profile,

FIG. 3A 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. 3B is an enlarged sectional view showing a semiconductor active layer constituting the semiconductor laser of FIG. 3A, and

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

Claims

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

2. A semiconductor layer as defined in claim 1 wherein a boron compound and at least one kind of metalorganic compound 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 base plate selected from the group consisting of a BeO base plate, a TiB2 base plate, an ScB2 base plate, a VB2 base plate, a YB2 base plate, an MnB2 base plate, an MgB2 base plate, an FeB2 base plate, and a CrB2 base plate.

4. A semiconductor layer as defined in claim 1 wherein the semiconductor layer is formed at a film formation temperature of at most 1,200° 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 metal organic 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: BxAlyGazN

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 electrode, the first electrical conduction type cladding layer, the semiconductor active layer, the second electrical conduction type cladding layer, and the second electrical conduction type electrode being formed on the first electrical conduction type semiconductor base plate,the first electrical conduction type semiconductor base plate being a base plate selected from the group consisting of a BeO base plate, a TiB2 base plate, a ScB2 base plate, a VB2 base plate, a YB2 base plate, an MnB2 base plate, an MgB2 base plate, an FeB2 base plate, and a CrB2 base plate,each of the first electrical conduction type cladding layer and the second electrical conduction type cladding layer being a BAlGaN layer, which has been formed by use of a laser assisted metalorganic vapor phase epitaxy technique,the semiconductor active layer being constituted of a single-layer or laminate structure containing a BGaN layer and/or a BAlGaN layer, which has been 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 semiconductor active layer is a multiple quantum well active layer, which is constituted of a laminate structure comprising BGaN quantum well layers and at least one barrier layer selected from the group consisting of a BGaN barrier layer and a BAlGaN barrier layer.

11. A semiconductor light emitting device as defined in claim 9 wherein 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.

12. 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 210 nm to 280 nm, or a light emitting diode, which has a center emission wavelength falling within the range of 190 nm to 300 nm.