JP2803375B2 - Semiconductor structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor material, and more particularly to an improvement in performance of a visible light semiconductor laser device.

[0002]

2. Description of the Related Art GaInP, AlGaInP, or AlGaInPAs mixed crystal semiconductor is a material for a visible light semiconductor laser. When the above mixed crystal semiconductor layer is epitaxially grown on a (001) plane and a substrate having a plane orientation equivalent thereto, The band gap energy (Eg) of the mixed crystal semiconductor layer changes depending on crystal growth conditions. For example, in GaInP, Eg is 1.83 to 1.9.
It is known that it changes by about 90 meV to 2 eV.
This change in Eg is caused by a change in the state of formation of an ordered structure that is naturally formed during crystal growth. (These are Physical Review Letters (Phys. Rev. L.)
ett. Vol. 60, page 2645 (1988)) This change in band gap energy has a direct correspondence with the change in oscillation wavelength when GaInP is used for the active layer of a visible light semiconductor laser device. When changing, a method of changing the epitaxial growth conditions can be considered.

Further, the growth surface has a group III surface (11).
a) When a crystal is grown on a plane (a = 1, 3, 5) or a plane (θ ≦ 6 °) obliquely inclined by an angle θ in the [110] direction from the (001) plane. A GaInP crystal having a large Eg is grown. Further, the growth surface has a (-111) step of group V, (-11b)
(Where b = 1, 3) Ga lattice-matched to the GaAs plane
It is known that InP takes a high Eg value of about 1.9 eV or more.

[0004]

Actually, when manufacturing an AlGaInP visible light semiconductor laser device by changing the oscillation wavelength by the metal organic chemical vapor deposition method (MOVPE method), the growth conditions are changed or the group III is used. When grown on a substrate orientation plane having a surface, the performance or reliability of the device is reduced, and it is impossible to change the oscillation wavelength of the device by changing the growth conditions. Further, when the crystal was grown on the (-111) or (-113) plane, only a crystal having a large Eg could be obtained. Thus, there is a problem to be solved regarding the wavelength control of the conventional AlGaInP visible light semiconductor laser.

An object of the present invention is to solve the above conventional problems and control the band gap of a semiconductor structure. In particular, it is an object to control the oscillation wavelength of the visible light semiconductor laser by controlling the order state in the crystal while using GaInP of the same composition for the active layer, thereby making it possible to take various wavelengths.

[0006]

According to the present invention, there is provided a semiconductor structure comprising: a substrate crystal having a plane orientation of (−11 m) (5 ≦ m ≦ 13) or equivalent; and a lattice constant formed on the substrate. Epitaxial growth is almost equal, and I
A mixed crystal semiconductor layer having an ordered structure on any of the atom sites in the II-V or II-VI mixed crystal semiconductor layer. The plane orientation of the substrate crystal may be any angle within 3 ° from the above orientation.

[0007]

In the present invention, (−11 m) [5 ≦ m ≦ 1
3] In the case where GaInP is grown on a GaAs substrate having a (−111) step plane of a V-group plane, an ordered state in a GaInP crystal epitaxially grown, that is, a natural superlattice (Natural superlattice) depends on the substrate plane orientation.
Super Lattice (NSL) is formed in a different state.

The operation will be described below with reference to FIG. FIG. 1 shows the off angle θ and G from the (001) plane to the [−110] direction.
It is a graph which shows the relationship of Eg of aInP. In the form of NSL, since the existence of (−111) V steps plays a role of promoting the formation of NSL, (−1, 1, 13) planes having a moderately high (−111) V step density are grown. When used on a surface, the order of the NSL increases, and
g is low.

In addition, in order to form NSL, in addition to the (−111) V step, the surface rearrangement structure of the V group atoms on the (001) plane covered with the V plane, that is, in the [−110] direction. The twice-period structure serves to promote the alternating arrangement of Ga rows and In rows extending in the [110] direction on the (001) plane.

This double period structure in the [-110] direction is difficult to be formed on the (-115) plane,
5) The Eg of GaInP on the surface takes 1.9 eV to a higher value. When these (-1, 1, 13) planes and (-115) planes are represented by off angles θ from the (001) plane to the [−110] direction, (−1, 1, 13) is θ = 6.2. °, (-1
15) becomes θ = 15.8 °, but 6.2 ° ≦ θ ≦ 1.
When GaInP is grown on a substrate having θ in the range of 5.8 °, the order of NSL type in the crystal decreases sharply with the increase of θ, and Eg is also 1.83e.
It changes by about 70 meV from V to 1.9 eV.

Although the operation has been described using GaInP, AlGaInP, AlGaInPAs and Group II
Ordered structure within the atomic site or group V atom site
The present invention can be applied to the group II-V mixed crystal having the same effect.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1 FIG. 2 is a sectional view showing a schematic structure of an AlGaInP visible light semiconductor laser according to a first embodiment of the present invention. By the MOVPE method on the n-type GaAs substrate 1 having a (-117) plane orientation in this embodiment, n-type AlGaInP cladding layer 2, Ga _0.5 In _0.5 P active layer 3, P-type AlGaI
After growing the nP layer 4 and the n-type GaAs current blocking layer 5 and providing a current injection region in the current blocking layer 5, the P-type G
The aAs electrode contact layer 7 is continuously grown. NSL is formed in the active layer of the double hetero junction thus formed.
Are formed, and the p-side electrode 7 and n
When the side electrode 8 was formed and laser oscillation was performed at room temperature, an element having an oscillation wavelength of 674 nm was obtained.

Embodiment 2 FIG. 3 is a sectional view showing a schematic structure of an AlGaInP visible light semiconductor laser according to a second embodiment of the present invention. In this embodiment, n-type GaAs having a (-1, 1, 11) plane orientation is used.
An n-type AlGaInP clad layer 10, a Ga _0.5 In _0.5 P-type layer 11, a P-type Al
A GaInP layer 12 and an n-type GaAs current blocking layer 13 are grown, a current injection region is provided in the current blocking layer 13, and then the P-type GaAs current contact layer 14 is buried.
Further, when a p-side electrode 7 and an n-side electrode 8 were formed and laser oscillation was performed at room temperature, an element having an oscillation wavelength of 689 nm was obtained.

As in Examples 1 and 2, even when the same composition GaInP and active layer were used, laser devices having different oscillation wavelengths could be obtained due to different substrate orientations to be grown.

On the same (-117) plane as in Example 1, the composition of the active layer was (Al _0.10 Ga _0.90 ) _0.5 In _0.5
By using a crystal made of P, an element having an oscillation wavelength of 653 nm could be obtained.

[0017]

According to the present invention, as described above,
Even if crystals having the same composition are used, visible light semiconductor lasers having different oscillation wavelengths can be obtained. In addition to laser, the present invention can be applied to control of band gap energy of a semiconductor layer of a light emitting element, an electronic device, and an optical functional element.

[Brief description of the drawings]

FIG. 1 shows a [110] direction or (−1) from a (001) plane.
10] direction, the substrate off angle θ and Ga _0.5 In _0.5 P
FIG. 4 is a diagram showing a relationship between band gap energies.

FIG. 2 is a sectional view showing an AlGaInP visible light laser according to one embodiment of the present invention.

FIG. 3 is a sectional view showing an AlGaInP visible light laser according to one embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 n-type (-117) GaAs substrate 2 n-type AlGaInP cladding layer 3 GaInP active layer 4 P-type AlGaInP cladding layer 5 n-type GaAs current blocking layer 6 P-type GaAs electrode contact layer 7 P-side electrode 8 n-side electrode 9 n-type (-1, 1, 11) GaAs substrate 10 n-type AlGaInP cladding layer 11 GaInP active layer 12 P-type AlGaInP cladding layer 13 n-type GaAs current block layer 14 P-type GaAs electrode contact layer

Claims (2)

(57) [Claims] 1. The method according to claim 1, wherein (−11 m) [5 ≦ m ≦ 13]
And its equivalent plane orientation or 3 from these plane orientations
A crystal substrate having a plane orientation having a deviation of less than or equal to three degrees, and a ternary or higher III-V epitaxially formed on the crystal substrate.
A mixed crystal semiconductor layer having an ordered structure in a group III atom site, a group V atom site, a group II atom site, or a group VI atom site in a group III or II-VI mixed crystal semiconductor. Semiconductor structure. 2. The method according to claim 1, wherein the mixed crystal semiconductor is GaInP or A.
2. The semiconductor structure according to claim 1, wherein the semiconductor structure is based on lGaInP or AlGaInPAs.