JPS6092687A - semiconductor laser equipment - Google Patents

Abstract

PURPOSE:To improve the heat radiation of the titled device and to lessen the stress accompanied with the generation of heat by a method wherein any one of two kinds of alloys made by making Cu contain uniformly in each of W and Mo whose thermal expansion coefficients are both in a specific extent, or an alloy made by making Cu contain uniformly in an alloy of the W and the Mo, is used as a material for the submount. CONSTITUTION:As a material for the submount of a semiconductor laser, wherein a semiconductor laser element 1 formed with GaAs, Gap or GaSb as the substrate has been used, is used any one of an alloy made by making Cu contain uniformly in W whose thermal expansion coefficient is in an extent of 5.0-8.5X10<-6>cm/cm. deg.C; an alloy made by making Cu contain uniformly in Mo, whose thermal expansion coefficient is also in the above-mentioned extent as well; or an alloy made by making Cu contain uniformly in an alloy of the W and the Mo. These alloys can be manufactured by a powder method or a solution-dipping method. When the thermal expansion coefficient of the material for the submount exceeds the above-mentioned extent of thermal expansion coefficient, the mismatching of the thermal expansion coefficient of the material and that of the semiconductor laser element 1 is increased. As a result, failure of the element or lowering of the luminous efficiency, etc., are caused due to stress, which generates in the element.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application This invention relates to a semiconductor laser device, and particularly to improvement of its heat dissipation characteristics.

(b) Prior Art Since semiconductor laser devices are current-driven high-power devices, they generate a large amount of heat during operation. Therefore, if a careful heat dissipation design is not carried out, there is a risk that heat generation during energization may cause deterioration of the focus, shorten the element life, or destroy the semiconductor laser element.

In general, a semiconductor laser element generally has temperature characteristics as shown in FIG. As is clear from the figure, the light emission output largely depends on the element temperature. To obtain an optical output of 2 + lW at 20 degrees Celsius, a current of approximately 8 (1 mA) is required, but when used at a temperature of 50 degrees Celsius, 3Q + oA can even reach laser oscillation. 2mW
To obtain this, a drive current of 60 +++ A or more is required. Moreover, if the drive current is increased to compensate for the 1°C decrease in optical output due to the temperature rise, the increase in 7i1 flow will cause an increase in the amount of heat generated by the element, causing a vicious cycle in which the element temperature will further rise. This can lead to rapid deterioration of the device or, in extreme cases, destruction of the device.

Therefore, the main stem supporting the semiconductor laser element needs to be made of a material with high thermal conductivity to improve heat dissipation.

Further, if there is a difference in the coefficient of thermal expansion between the stem and the semiconductor laser element, distortion occurs due to heat generation, and unnecessary S)L/nu is added to the semiconductor laser element. Such stress accelerates the deterioration of the performance of the semiconductor laser element and even causes its destruction.

Therefore, the material for the stem is required to have high thermal conductivity and a coefficient of thermal expansion as close as possible to that of the semiconductor laser element.

Therefore, conventionally, as shown in FIG. 1, the semiconductor laser element l was attached to the block 3 inside the mount of the package via the submount 2, and the material of the submount 2 was Kovar/L/(trade name). Materials exhibiting low thermal expansion properties have been used.

(c) Problems to be Solved by the Invention As mentioned above, the material of the submount 2 is required to have good thermal conductivity and a coefficient of thermal expansion close to that of the semiconductor laser element.

However, as shown in Table 1, conventionally used cobalt has a coefficient of thermal expansion very close to that of semiconductor laser element 1, but it has a problem of low thermal conductivity, which makes it difficult to improve the performance of semiconductor lasers. This was a major obstacle at the top.

B) Means to solve the opening point The present invention is directed to a semiconductor laser using a semiconductor laser element having a substrate of GaAs, GaP or GaSb, and in this case, the coefficient of thermal expansion is 4;t It of the submount. is 50~8.5 X I Oc〃V/am・“
The following metals in the range of C, namely (+l Alloy containing Cu uniformly in W+21M0K
Alloy containing Cu uniformly! 31 C in W-Mo alloy
It was decided to use one of the alloys containing u uniformly.

The above alloys can be manufactured by a powder method or an infusion method.

If the submount material exceeds the above-mentioned non-expansion coefficient range, there will be a large mismatch in the thermal expansion coefficient with the semiconductor laser element, resulting in stress on the element, damage to the element, or a decrease in luminous efficiency. .

Further, the Cu content of the metal material satisfying the thermal expansion coefficient in the above range is as follows in weight %.

W-Cu: 0.5-80% (MiJ (metal material 11) Mo+Cu: 5-35% (metal material (2) above) W-MoCu: 0.5-85% (metal material (3) above) )The thermal conductivity of the above metal material is
035-070 are/am-max.°C.

For reference, the comparison between the metal material of this invention and the conventional example (Kovar) and the coefficient of thermal expansion of the element substrate are as follows:
As shown in the table.

Table l As can be seen from Table 1 above, in the case of the present invention, the coefficient of thermal expansion is extremely close to that of the element substrate of a semiconductor laser device, and the thermal conductivity is improved by more than a factor of pro than the conventional Kovar. There is.

(E) Example A semiconductor laser device having a double hetero 114 structure in which JGaAs was epitaxially grown on a GaAs substrate,
A semiconductor laser device was manufactured in which a submount material was made of a W--Cu alloy containing 15 parts by weight of Cu and was fixed to a mounting block.

The coefficient of thermal expansion of the submount material in this case is 65XIO
cm/cm・”c, s thermal conductivity is 0.60d/G・5e
It was e-”C.

The temperature rise of the element of the semiconductor laser device described above was reduced by about 25% compared to the case of Kovar.

Furthermore, compared to conventional products, the luminous efficiency is approximately 70% longer and the lifespan is approximately 100 times longer.

It was confirmed that the higher the Cu content, the better the heat dissipation characteristics.

(f) Effects As described above, according to the present invention, it is possible to obtain a semiconductor laser device with good heat dissipation and less stress caused by heat generation. Furthermore, as shown in FIG. 3, a package structure in which the submount and the mounting block were integrated could be easily created.

[Brief explanation of drawings]

FIG. 1 (al is a top view of a conventional semiconductor laser device,
Fig. 1 (bl is a cross-sectional view at AA'). Fig. 2 is a drawing showing an example of the light emission characteristics of a semiconductor laser.
Figures (,) are top views showing an example of the semiconductor laser device of the present invention, and Figure 3 (bl is a cross-sectional view at BB'. In the figures, each number means the following. Same number 1 shows corresponding parts in each drawing. 1: Semiconductor laser element 2: Submount 3: Mounting block 4: Light extraction window 5: Cap 6: Package body, i.e., stem 7: First lead wire 8: 2nd rl 9: Insulator IO = Lead wire factor t 1 run mouth 7 connections

Claims (1)

[Claims] il) A semiconductor laser device in which a semiconductor laser element having a substrate of GaAs, GaP or Garb is attached to a stem of a package via a submount, in which the material of the submount has a thermal expansion coefficient of 50
C in either W, Mo or 'W-MO alloys in the range <-8,5
A semiconductor laser device characterized by using an alloy uniformly containing u. (2) The semiconductor laser device according to claim 1, wherein the stem is made of the same material as the submount. (3) The semiconductor laser device according to claim 2, wherein the stem and the submount 1 are integrally molded.