JPS60145693A - Surface light emitting type semiconductor laser device - Google Patents

Abstract

PURPOSE:To inhibit wavelength shift due to the variation in band gap based on temperature changes by obtaining specific wavelength selectivity by a method wherein a multilayer periodical structure of a semiconductor film having a thickness (1/4+m/2) times (where, m=0,1,...) as large as the intracrystal wavelength of a generated laser beam is formed in the crystal. CONSTITUTION:When a forward voltage is impressed across an anode 5 and a cathode 6, the first and second P<+> Inp layers 14, 15 and the second and third P<+> InP layers 17 and 18 are biased in reverse direction; however, a current path generates by tunnel effect, and current flows as broken line arrows I. Carrier inversion distributed regions 21, 22, and 23 are formed at the centers of the first, second, and third P type InGaAsP active layers 13, 16, and 19, respectively. Then, induced emission occurs and causes reflection at the junction planes between the first-third P<+> type InP layers 12, 15, and 18 and the first-third P type InGaAsP active layers 13, 16, and 19, resulting in multiplex reflection. The thickness of each layer becomes 1/4 of the intracrystal wavelength of light in order that with respect to each layer a reflected light and an incident light strengthen each other under the same phase in the crystal.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a surface-emitting semiconductor laser device, and particularly to a structure thereof that has specific wavelength selectivity.

[Prior art]

Figure 1 is a cross-sectional view showing the configuration of a conventional surface-emitting semiconductor laser device.
, (2+ is formed on the indium gallium arsenic phosphorus (nGaAs,
P), (3) is the n-carved nPI(i) formed on the active@(2), (4) is the p-carved nP layer (1)
(5) an insulating film formed on the lower surface of and having an opening in the center;
is formed thereon and in the opening part p carving nP 1
4 An anode electrically connected to (1), (6) a cathode formed to electrically contact the upper surface of the n-carved nP layer (3) and having an opening in the center, and (7) this cathode. This is a dielectric film that covers the surface of the n-carved nP layer (3) exposed in the central opening of the cathode (6).

In this conventional example, when a positive forward voltage is applied to the anode (5) and a negative forward voltage is applied to the cathode (6), a current flows as indicated by the dashed arrow, and in the central part (8) of the active layer (2). The carrier density is high, that is, carrier population inversion occurs.

Stimulated emission of photons occurs. Then, the resonator formed by the interface (9) of the p/i nP layer (1) and the anode (5) and the interface (10) of the n carved nP layer (3) and the dielectric film (7) is illuminated. goes back and forth as shown by the arrow, is amplified,
Emits laser oscillation. A part of this light passes through the dielectric film (7) and is emitted as shown by arrow A.

By the way, in this conventional surface-emitting type semiconductor laser device, an induced number circle shines on the main surface (9) on the semiconductor layer side.

However, since each layer (1) to (3) does not have a periodic structure, it does not have wavelength selectivity.

There were drawbacks such as large wavelength fluctuations due to band gap fluctuations caused by heat.

[Summary of the invention]

This invention was made in view of the above points, and the thickness of each layer on the semiconductor substrate is optically (1/4+II]/,) times the wavelength of the oscillating laser light (where m=o, l). .

2. Providing a surface-emitting semiconductor laser device with a specific wavelength selectivity by growing a multilayer film with a periodic structure inside the crystal and multiple reflections between the multilayer films. It is something to do.

[Embodiments of the invention]

Figure 2 is a sectional view showing the configuration of an embodiment of the present invention, and the same reference numerals as in Figure 1 indicate the same parts. In this example, metal organic vapor phase epitaxy (MOOVD) was applied on a p-type np substrate αB.
) method to form a first p+ type I heavily doped with p-type impurities.
nP layer (2), on top of which is a first p-type layer (nP) with a narrower bandgap than the InP layer; on top of that is a first p-type layer (nP) with a GaAsP active layer; Layer α Xun,
, and on top of that, the following second p+ shape nPIiQd
, v; 2nd p-shaped nGaAsP active layer αQ, 2nd n+-shaped button P layer αη, 3rd p+-shaped nP layer u, 3rd p-shaped nGaAeP active layer O1, and 3rd n+-shaped button The nP layers CL are sequentially laminated, and the insulating film (4) and anode (5) are on the bottom surface of the p-type InP substrate (1), and the cathode (6) having an opening is on the third n+ type nP layer. It is formed on the top surface of (a).

In this example device, the anode (5) is positive and the cathode (6)
When a forward voltage is applied so that n becomes negative, the first n
+ forming nPliiQ4) and second p+ forming nP layer (1G
and the n+ form of the 2nd nPI sound α force and the 3rd p+
Although it is biased in the opposite direction between the shaper nPl@Ql,
A current path is created by the tunnel effect, and the current flows as indicated by the dashed arrow. And the carrier population inversion region @
1), (a) and (c) are respectively the first. The second and third p-carved nGaAθP active layers (2) are formed in the central portions of the a and a layers, and stimulated emission occurs. Stimulated emission light is the first. 2nd and @3 p+ shaped nP layer (2),
αe and (g), respectively. second and third p
Reflection occurs at the joint surface between the carved nGaAF3F active layer α3, (16 and α), resulting in multiple reflections.Therefore, for each layer, the reflected light and the incident light become in phase inside the crystal, and the light strengthens each other. As shown, the thickness of each layer is 1/4 of the intracrystal wavelength of light.For example, the wavelength of InP-based light is 1/4.
．． 2.IIm, the thickness of each layer will be about '730A when the refractive index is 4.1. Stimulated emission light due to multiple reflections stably generates unique oscillation due to the periodic structure inside the crystal, and a part of the light is emitted from the opening of the cathode (6) in the direction perpendicular to the crystal layer in the direction of arrow A. radiated as shown. The size B of this light outlet is set to about several μm so that the horizontal fundamental mode fl is achieved.

In addition, in the above embodiment, the semiconductor material was
Although the example using p/nP is shown, other ■-V group compound semiconductors, ■-■ group compound semiconductors may also be used, and it goes without saying that the arrangement of p-type and n-type may be reversed. It is.

In addition, the thickness of each layer was set to /4 of the intracrystalline wavelength of light, but generally it is (1/10]/2) times (however, m-0゜1,
2,------) K.

〔Effect of the invention〕

As explained above, in the surface emitting type semiconductor laser device according to the present invention, the internal wavelength of the generated laser light is (1/4+In/2) times (where m=0°1, 2)
Since a multilayer periodic structure of semiconductor films with a thickness of , -------) is formed, specific wavelength selectivity can be obtained, and wavelength shifts due to band gap fluctuations due to temperature changes can be suppressed.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the structure of a conventional surface-emitting type semiconductor laser device, and FIG. 2 is a sectional view showing the #I configuration of an embodiment of the present invention. In the figure, a is a p-carved nP substrate (first conductivity type semiconductor substrate), @, α6, QIIO is a p+ type nP layer (first semiconductor film), α3, (1, α Samurai is a p-carved nGa
AsP layer (second semiconductor @), Q43, αno,
(a) A n+ shaped nP layer (third semiconductor film). Note that the same reference numerals in the two figures indicate the same or corresponding parts. Agent Masuo Oiwa Figure 1 Figure 2

Claims (1)

[Claims] (1) A first semiconductor film of a first conductivity type with a high impurity concentration and a first conductivity type semiconductor film on a semiconductor substrate of a first conductivity type;
a second semiconductor film having a smaller forbidden band width than the first semiconductor film;
A three-layer film structure consisting of a semiconductor film of Koshirae 3 having a high impurity concentration of a second conductivity type opposite to the first conductivity type and having a forbidden band width equal to that of the first semiconductor film is repeated multiple times. The film thickness of each semiconductor film is (1/, 10/2) times the wavelength within the semiconductor crystal of the laser light to be generated (where m=o, l). , 2. ---=).