JPS594194A - Semiconductor laser device - Google Patents

Abstract

PURPOSE:To obtain a semiconductor laser device of the structure which can obtain high output by providing a portion which varies discontinuously for the depth direction of a striped groove formed in width on the surface of a substrate to become the grown base of the layers including an active layer. CONSTITUTION:A groove which has 1.5mum of depth and 4mum of width is formed in (011) direction on the (100) surface of an N type GaAs substrate 25, and the first layer N type Ga0.65Al0.35As clad layer 26 of approx. 1mum at the flat part of the substrate at both sides of the groove, the second layer non-doped Ga0.95 Al0.05As active layer 27 of approx. 0.1mum, the third layer P type Ga0.65Al0.35As clad layer 28 of approx. 1.5mum and the fourth layer N type GaAs layer 29 of approx. 0.5mum thick are sequentially grown and formed on the surface of the substrate. The shape of the groove at this time is deformed in the shape varying discontinuously in the depth. Then, an Si3N4 film 30 is formed on the grown surface, a striped window is formed on the top of the groove of the substrate, the film is diffused, so that the end of the diffused surface reaches the third P type Ga0.65Al0.35As clad layer 28. Thereafter, the film 30 on the surface is removed, a P type side electrode metal is deposited, and alloyed, thereby forming a P type side ohmic electrode 32.

Description

[Detailed description of the invention] The present invention relates to a semiconductor laser device.

In recent years, much effort has been made to develop semi-binary lasers that emit stable fundamental transverse mode oscillations as pickups for video discs, digital audio discs, and the like.

Ko 1. An effective method for realizing the entire structure is to form all the grooves on the substrate.

FIGS. 1(a) and 1(b) are an example of a conventional semiconductor laser in which all grooves are formed in iJ: substrate. Figure 1 (21) shows a laser with a Nishijyo C8P structure, in which a groove with a flat bottom is etched on the substrate, and each layer of the double layer structure, including the active layer, is grown on top of the groove. It is something.

Figure 1(b) f<:l, shape of this groove7. Figure 1 (c) iJ', '(t
It is shaped like an iU-shape. In these figures, 1 is an n-type GaAs substrate, 2 is an n-type Cra1. ,XA
lXAs cladding layer, 3)71゛-b0'', , A
IYAs active layer, 4bp type Ga1-XAIXAs cladding layer, 5 (d n !1iIj GaAs layer, 6
U! 1fi - a lead diffusion region; 7 a p-side ohmic electrode 11'' metal film;

In the semiconductor lasers having the structures shown in FIGS. 1(a), (b), and (Q), the first ground layer 2 is formed to be thinner on the outside of the groove and thicker on the groove part, and inside the active layer 2. light leaks to the board J1. The active layer 2 is provided with a refractive index distribution based on the difference in absorption loss due to the absorption loss. As a result, the oscillation transverse mode is confined C) within the active layer 2 of the 1° trench JH.

By the way, the best! [1 of VC disk files etc.
! - For the first month of input, a 17-body laser was required due to its fundamental transverse mode oscillation and high output power.

′? flL interview), (: Provisional ``Achieving high output with an IL centrifugal laser &:]:, Absorption to J114 handling] 11 Reduction of failure and bar density per unit cross-section bond.・
In order to reduce the likelihood distribution in the plane perpendicular to m, it is necessary to make it as wide as possible.
In the semiconductor laser of 1゛A), the third layer cladding layer 2 is I', ff/f is thick on the vertical side flat GL (and thick on both sides of the groove, and gradually thicker near the side surface 1). Nari, 771
14 layers of fur on medium heat 9)<13 minutes until the turtle is fully closed 1
/\mera n/! :) 4'! I' degree no ν? Because it is a comb, both sides of the groove ((n) There is significant absorption into the substrate in the cladding layer near f.j. If the taper is widened, the 4t'' loss in a part of the taper increases, and as a result, the external differential quantum efficiency decreases.On the other hand, if the ff/f is formed so that the taper part becomes narrow, the depth of the groove becomes shallow. , if the thickness of the cladding layer at the center of the groove is sufficient, 71 will disappear.
In the case of a semiconductor laser having a V-groove path shown in FIG.

Uninvented Q-1 We have improved these shortcomings and achieved high output! The present invention provides a semiconductor laser device that is immersed in water (1?).

1.--In the embodiments of the non-invention along with the drawings! 1″:
The conductor laser device 6 will be described and explained.

n gljノ1(,l&25.11'(Tip2('X
I (aHC-r J: f'f/i which changes discontinuously from fz depth fi is provided. On the surface of the base 414, liquid phase Eitagi/yaru θ, ni, Vsu, first layer n-type cladding is provided. layer 26,
2nd layer horn-doped active +11 layer 27, 1st layer n-type cladding layer 28, 4th layer n-type current limiting layer 29
Serve (Figure 2 (b)). Next, the p-type impurity gold (gold) IL(l)ri/I'f'jfl is selectively diffused in stripes from the growth surface, and the diffusion front reaches the third cladding layer 28.
Reach VC. 1: Sea urchin (Figure 2 (C)). After removing 30 films on the surface for selective diffusion, 32 p-side ovens are formed. Further, an n-side open circuit f&<33 is formed on the Ji side, and the fabrication is performed as shown in FIG. 2(d).

Semiconductor laser device σ of this structure, Fig. 1f&) and (b
) has a wider distribution of IL running force/(Y) in the direction perpendicular to the active layer, and also has a longer tapered part on both sides of the groove. By making the cladding layer 26 shorter, the cladding layer 26 can be made thicker over a wider area, and the total absorption into the substrate can be reduced to a minimum of 1. Furthermore, compared to the structure shown in Fig. 1 (Q), by providing a taper [3] at the edge of the groove, the change in refractive index between the grooves (11 and 1) is made gentler. The fL allows the width of the groove that can be oscillated by the basic transverse motor to be widened, and has the advantage of being able to achieve even higher output.

Hereinafter, an embodiment of a semiconductor laser device 6 of the present invention will be shown, which is constructed from FMCGaAs ('5at-xAlzAs system).

(100) of plate 26 on n-type GaAs) - Ni no 11
Grooves with a depth of 1°5/J and a width of 4 μm are completely formed in the > direction to form a shape as shown in Fig. 3. Liquid phase epitaxy method VCJ on the substrate surface with grooves: (1st) @ n-type Gao, 65
A1 o, 55As The crat layer 26 is approximately 1/nm thick on the flat parts of the substrate on both sides of the groove, and the second layer horn is 95A.
1cosAs fjQ Ikui 2A approximately 0.1μm,
The third layer p + (17Gat+, 6sA1o, 55As cladding layer 28 is about 1.5 μm thick, the fourth layer n Qlj Ga
The As layer 29 is formed continuously to a thickness of about 0.571 m and a length of 1 jlE to form V layers as shown in FIG. 2(b). At this time, the shape of the groove is deformed by meltback into a shape in which the depth changes discontinuously as shown in the 21st line 1(a). The width of the upper part of the groove is set to about γμm. next vc
+Jvi; k f) And Si 5N41d7307
2. Form a stripe-shaped window in the substrate groove lx part, perform diffusion there, and the tip of the diffusion surface will reach the third p-type Ga c65A1o, 35AS cladding layer 28. (Figure 2 (C)). After that, 5i on the surface
3Na film 30 is completely removed, p-side electrode metal is vapor deposited, and alloying is performed to form 32 full ohmic electrodes. On the substrate side VC, an n1+111 electrical metal is deposited and alloyed to form 33 n-light ohmic electrodes (FIG. 2(d)). The semiconductor wafer prepared as shown in ζ is cleaved and mounted on the S1 block to complete the process.

With this ('#f-built 'l'ii?7 body laser device,
We were able to achieve a high optical output of 60 mW with fundamental transverse mode oscillation.

In the above embodiment, the GaAs-GaAlAs semiconductor laser device i'Vf was opened, but the InP-InGaA
Exactly the same effect can be expected in the present invention with lasers using other mixed crystal fibers such as sP. As for the shape of the wide groove, in the example, we took up a case in which the groove was completely sloped, but in Figure 4 (IL) 3, the depth of the groove changes in a step-like manner. 2) Is it t-1', isotropic as shown in Figure 4(b)? Carve f'i b! 21.
1i1-like effect 1) also brings about busyness.

1-Explained. 1: Sea urchin P of the present invention! u f4-
1. In the Rayleigh device, it is possible to completely stabilize V'C in the baseless transverse mode.
)I, so the song 1 of the above Y is blasphemous.

[Brief explanation of the drawing]

Figure 1 (a), (b), (Q) Introduction to the Continuing Song Dynasty (1) ゛Cross-sectional view of the integrated laser device, Figure 2 (a)
~(d) (r, r An embodiment of Mitsuaki Ki's vcb/manufacturing of a semiconductor laser device; 1. Cross-sectional view at "1" on top A, No. 31, No. 1, FIG. 4(a) , (t)) l','L:
1"i'i'; is a sectional view showing the shape of a substrate related to a bright semiconductor laser device. 1, ... - n-type GaAS based, 2-- n-type Cr
a, -, Al, As cladding layer, 3...non-doped Ga, -YAl, A 1/1 layer, 4--
p-type Ga, , AlXAs layer 71, 6- =-
n 11; llGaAs layer, 6... dilead diffusion region, Y...p 11111 ohmic electrode (-Sis River metal film, 8...n 1llI ohmic electrode (metal film for station, 25-... ...n-type GaAs substrate, 26...n
type eal XAIXAS cladding layer, 27 =-non(
・-Zo Gu,,YAIYAs/Uranus 1'l l+”
i, 2 8--p) eS Cra, , Al, As Cra CIl layer, 29... n-type GaAs, 30.
... Insulating film, 31 ・ Curved lead expansion 11g iiτ branch area, 3
2-...p side ohmic city ＼ j mon fri 1. Old 1σ, 33
-... n side Ohic Den] 4Zj month age genus membrane 1, agent's name fu 1'! Science I-Toshi Nakao Male Haga 1
Figure 1 Figure 2 Figure 3 (p) (b)

Claims (1)

[Claims] A semiconductor laser device having a partial cure in which the groove width of a striped groove formed on the surface of a substrate, which is a growth base for each layer including an active layer, changes discontinuously in the depth direction of the groove.