JPH04176180A - Semiconductor laser element chip - Google Patents

Abstract

PURPOSE:To enable a semiconductor laser element chip to be set stable in characteristics and high in reliability by a method wherein a film of Al2O3 or SiO2 is laminated as a final layer of an alternately laminated dielectric multilayer film, and the film of Al2O3 or SiO2 is coated with epoxy resin. CONSTITUTION:A GaAs/AlGaAs double-heterostructure is formed on a GaAs substrate, a photoprocess and an electrode forming process are carried out, the wafer concerned is cleaved into a bar 4, the opposed cleaved planes of the bar 4 are coated with a dielectric multilayer film 2. The dielectric multilayer film 2 is deposited through a vacuum evaporation method in such a manner that films of Al2O3, TiO2, Al2O3, and TiO2 lambda/4 in thickness are alternately laminated in this order, and then a film of Al2O3 is deposited thereon as thick as lambda/2. In succession, The bar 4 is split into a large number of chips, the chip 1 is die-bonded to a lead frame 5 making its substrate face upward, and the substrate is wire-bonded. Finally, the chip 1 and its vicinity are molded with an epoxy resin 3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a semiconductor laser chip having a dielectric multilayer film formed on a laser source emission surface.

[Conventional technology]

The reflectance of the chip of the semiconductor laser element is controlled on a pair of open-arm surfaces that are located on opposite sides and form the original resonator. This state is shown in FIG. FIG. 4 is a schematic cross-sectional view of the periphery of the chip 1 viewed from the side, and the fat pad multilayer film 2 is coated on each of the two open surfaces of the chip 1. The arrow indicates the direction of laser light emission.

The reflectance of the two divided planes of chip 1 greatly affects device characteristics such as threshold current, imitative fractional quantum efficiency, and intensity noise.
It is controlled according to the element Kawagoe.

For example, in the case of a laser device with a tube head output plate, the rear reflectance is set to 90.
% and lowering the front reflectance of the light exit surface to about 10%, it is possible to efficiently extract laser light from the 11j plane.

The reflectance of the dielectric layer N film 2 is Al1203 (low refractive index).
Refractive index: 1.65) or 5i02 () Output index: 1.50
)and.

High U (Amorphous % of refractive index S+ (Refractive index: 3.4) T
, '102 (refractive index: 2.2) and the oscillation wavelength (
λ) (') They are alternately laminated with a film thickness of 32 h]. Fig. 5 A-1a is a diagram showing the relationship between the reflectance and the film thickness of the dielectric multilayer film 2 consisting of 203 and T+02, ApGa I-x As (x=0.1
7) A, β203, T 702 (1) II on top
For example, if we borrow the reciprocal rate of 7 (n%) by 1, then klJ 20 , + and TiO2 are 2. After layer by layer, it is usually rolled from point 1III0) A in Figure 5 to a thickness similar to that of 5Ap203. This is because it is possible to maintain a reflectance of about 70% by properly controlling the film thickness and laminating the film, so it is not necessary to use A-gzQ3 with false θ scratches. Even if the reflectance deviates from the desired value, the reflectance can be maintained at least at point B in FIG. 5, and the plowing force is 1.

[Problem to be solved by the invention j As can be seen from FIG.
1) The variation of the reflectance with respect to the film thickness ζ is large, especially when controlling the reflectance near 7 (1%), as mentioned above.
Depending on the controllability of AJhOa accumulated at the end, one reflectance can be 4 or 4 as shown in the range of points A and B in Figure 5.
There is a layering property that varies from 0% to 70%. As a result, the characteristics of the semiconductor laser device also fluctuate. The dielectric multilayer film 2 is usually formed by vacuum evaporation, but it is not easy to suppress variations in reflectance of 2 or more, and the characteristics of the device change. This is a major cause of variation.

The present invention has been made in view of the above-mentioned points, and an object thereof is to provide a semiconductor laser element chip having a multilayer film with a reflectance of 1 that can be easily controlled on the laser beam emitting surface of the chip. .

[Means to solve the problem]

In order to solve the above problems, the semiconductor laser chip of the present invention has a dielectric multilayer film of -0203 or -0203.
iOz is laminated alternately to a thickness equal to the laser oscillation wavelength, and as the final layer, A, e203 or SiOz is deposited to a thickness of 1/2 the laser emission wavelength, and this is further coated with epoxy resin. This is what I did.

[Effect]

Since the semiconductor laser probe chip of the present invention is configured as described above, the final layer Al1 has a refractive index close to that of the epoxy resin.
Changes in reflectance due to changes in film thickness of 203 or S+02 are small, and the characteristics of the semiconductor laser device after assembly are stable.

[LOL example]

The present invention will be explained below based on examples.

Here, the present invention will be described using Ga A with an oscillation wavelength of 780 nm,
s/klJ Ga AS-based semiconductor laser chip.

A, the case where aT is covered with a dielectric multilayer film of e203 and Ti0z will be explained. Figure 3 fal, fbl, f
cl shows an outline of the process of assembling and manufacturing a semiconductor laser device from the chip ζ of the present invention.

A GaAS/AI3GaAs double heterostructure was formed on a soot, GaAs substrate by MOCVD (metal organic chemical vapor deposition), and after going through a photo process and an electrode formation process, this wafer was made into a wafer with a width of 260 PfrL, A bar 4 having a length of about 10 am is pleated. Next, the dielectric multilayer film 2 is punched out on a pair of opposing opening surfaces of the bar 4 (see Figure 3, fal J). The dielectric multilayer film 2 is deposited using the true nitrogen deposition method, and AJhOa is the deposition temperature of 400.
℃, deposition rate 5 A/s, and T iOz at a deposition temperature of 20
A-4h 03 at 0°C and deposition rate of 0.4 A/sec.
, T iOz , AJh O3*l1 of TiO2
After alternately laminating 111 m with false film thickness, AA 20
A is deposited outside the film thickness, and this is performed on the two interfold surfaces under the same conditions. Next, this bar 4 has a thickness of 320 μm.
The chips are separated into a large number of chips with the length of , and the chips are die-bonded onto the lead frame 5 with the substrate side up, and the substrates are wire-bonded [FIG. 3(b)]. Finally, mold the area around the chip with epoxy resin 3.
Figure (C)].

Here, the dielectric multilayer film 2 is S instead of the A swamp 203.
iOz may be used, or after amorphous [Si and TiOz are alternately laminated with a false film thickness, A, 8203 niOz, or 5iOz may be deposited as a final layer with a non-film thickness.

Furthermore, the semiconductor laser element does not have the resin molded package structure as described above, but may have a structure in which the end face of the dielectric multilayer film 2 laminated on the laser light emitting surface of the chip 1 is covered with the epoxy resin 3. good.

FIG. 1 is a schematic cross-sectional view of the periphery of the chip 1 of the semiconductor laser cable obtained in this way, seen from the side.

The difference between Figure 441 and Figure 4 is that AJhO3 and Ti0
2Q) Add ζ epoxy resin I resin 3 to the dielectric multilayer film 2.
is being deposited.

FIG. 2 shows the relationship between the thickness of the film J and the reflectance of the dielectric multilayers 1 and 2 in this case. Compare Figure 2 with Figure 5. As you can see, the refractive index of A13203 or Si02, which is the final layer of @Kametaitataneh:a2, is the refractive index of the resin (1,5). Since they are almost equal, if the resin is coated sufficiently thickly, the change in reflectance due to the change in reflectance of %A-e203 or 5i(h) will also be small.

The first comparison is a comparison of the characteristics of this semiconductor laser element and a conventional element by measuring 50 of them.

As shown in Table 1, the average value of the device using the chip according to the present invention is almost the same as that of the conventional device;
The standard deviation value is very small, reflecting the small variation in reflectance.

〔Effect of the invention〕

The chip of the semiconductor laser probe has a dielectric multilayer film on its laser light emitting surface, and normally one layer of dielectric material with a thickness of 2@ is formed on top of it to determine the reflectance. While it was difficult to control the reflectance and the characteristics of the semiconductor laser device were unstable, in the present invention, as described in the embodiment, two layers of A-e 20 a and TiO 2 are alternately formed with a film thickness of 24 mm. The laminated structure has a thickness of A-0203'/2, and is further coated with an epoxy resin whose refractive index is almost the same as that of the A-0203'/2 film, so even after assembly into a semiconductor laser device, fluctuations in reflectance are extremely small, and the device characteristics are improved. It was possible to improve the reliability by setting the same as above.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of the periphery of the semiconductor laser element chip of the present invention, FIG. 2 is a diagram showing the relationship between the total film thickness and reflectance of the dielectric multilayer film used in the present invention, and FIG. 4 is a schematic cross-sectional view of the periphery of a conventional semi-integrated laser confectionery chip, and FIG. 5 is a diagram of the gold film of the dielectric multilayer of the conventional chip. FIG. 2 is a diagram showing the relationship between JEJ and reflectance.

Claims (1)

[Claims] 1) A dielectric multilayer film laminated on a laser beam emitting surface, a dielectric layer film made of Al_2O_3 or SiO_2 as the final layer, and a resin covering this dielectric layer film. A semiconductor laser device chip. 2) In the semiconductor laser device chip according to claim 1, the dielectric multilayer film includes Al_2O_3 or SiO
_2 are alternately laminated with a thickness of 1/4 of the laser oscillation wavelength,
1. A chip of a semiconductor laser device, characterized in that Al_2O_3 or SiO_2 is deposited as a final layer to a thickness of 1/2 of the laser oscillation wavelength, and then coated with an epoxy resin. 3) In the semiconductor laser device chip according to claim 1, amorphous Si and TiO_2 are alternately laminated on the dielectric multilayer film with a thickness of 1/4 of the laser oscillation wavelength, and the final layer is Al_2O_3 or SiO_2. A chip of a semiconductor laser device, characterized in that the chip is deposited to a thickness of 1/2 of the laser oscillation wavelength and then coated with an epoxy resin.