JPH0538871U - Melt box for liquid phase growth - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a melt box for liquid phase growth in which an active layer having a high growth rate can be formed with a small thickness and with good controllability. In the melt box for liquid phase growth in which a semiconductor substrate is placed on a slide board and the slide board is moved to bring the solution into contact with the semiconductor substrate to perform liquid phase growth epitaxial growth, a batch melt introduction part 24
Then, a thin film growth solution reservoir having a contact opening 25 for contacting the semiconductor substrate 21 with a width smaller than the width of the batch melt introduction part 24 in the moving direction of the slide board 22 is provided.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a semiconductor laser device manufacturing apparatus, and more particularly to a melt box for liquid phase growth used in liquid phase epitaxial growth used therein.

[0002]

[Prior Art]

 Conventional techniques in this field include, for example, "Introduction to Semiconductor Lasers" by Nao Nakajima, published by Akiha Shuppan, P. 58-59. FIG. 4 is a cross-sectional view of a melt box for liquid phase growth for liquid phase growth using such a typical slide board. Here, the description is made by taking the liquid phase epitaxial growth of AlGaAs system as an example, but the same applies to InGaAsP system.

In this figure, reference numeral 1 denotes an InP substrate, which is fixed on the slide board 2 and moves together with the slide board 2. 3 is a carbon melt box for storing an In solution 4 (melt) in which Ga, As, P, etc. are supersaturated and melted, and the solution pool of this melt box 3 penetrates to the bottom with the same width. It is in contact with slide board 2. The slide board 2 is fixed to the board body 5 of the melt box 3. The lower part can be slid to the left and right by operating the push rod 8 from the outside. In addition, 6 is a thermocouple and 7 is a quartz tube.

The InP substrate 1 is contacted with the solutions I, II, III and IV in this order, and a desired epitaxial growth layer is formed on the InP substrate 1. For example, as a substrate, a p-InP substrate, I to p-InP melt, II to InGaAsP-melt (λg = 1.55 μm), III to n-InP melt, and IV to n-InGaAsP-melt (λg = 1.3 μm) 5), by appropriately controlling the contact time, as shown in FIG. 5, the InP substrate 11, the p-InP clad layer 12, the InGaAsP active layer 13, the n-InP clad layer 14, the n-InGaAsP are formed. It is possible to obtain a DH (Double-Hetero) structure in which the cap layer 15 is sequentially grown in liquid phase.

At this time, a thickness controllability of the InGaAsP active layer 13 is about 0.1 μm. The InGaAsP-based active layer with a particularly long wave has a high epitaxial growth rate, and the contact time is shortened by passing it through the substrate and under the solution [about ν = 20 (mm / sec)] to form a thin epitaxial growth layer. To do. This control of the active layer thickness is important for producing a semiconductor laser having particularly good characteristics.

[0006]

[Problems to be solved by the device]

 However, in the above conventional device, the growth rate of the active layer having a long wavelength of InGaAsP-based oscillation wavelength λg (λg ≧ 1.4 μm) is high, and the moving speed of the slide board has an upper limit. There is a problem that it is difficult to form a thin film (thickness ≤ 0.1 μm) with good controllability.

The present invention eliminates the above-mentioned problems in liquid phase growth, and provides a melt box for liquid phase growth capable of forming a thin active layer having a high growth rate and good controllability. To aim.

[0008]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention is to mount a semiconductor substrate on a slide board and move the slide board to bring the solution into contact with the semiconductor substrate for liquid phase growth for liquid phase growth. In the melt box, a batch melt introducing part and a solution reservoir for thin film growth having a contact opening for contacting the semiconductor substrate with a width smaller than the width of the batch melt introducing part in the moving direction of the slide board should be provided. It is the one.

[0009]

[Action]

 According to the present invention, as described above, a thin film growth having a contact opening for a solution and a semiconductor substrate having a width smaller than the width of the batch melt introducing section in the moving direction of the batch melt introducing section and the slide board. Since the solution reservoir is provided, the contact time of the melt at the contact opening with the wafer can be effectively shortened, and the active layer can be thinly formed with good controllability.

[0010]

【Example】

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a sectional view of a melt box for liquid phase growth showing an embodiment of the present invention, and FIG. 2 is a view showing manufacturing of a source ingot showing an embodiment of the present invention. As shown in these figures, since the solution is a solid at room temperature, it is usually soaked at a suitable temperature for a certain period of time using a device having a structure as shown in FIG. 2 to form a source ingot called a batch melt. ..

Explaining this point, first, pure In and InP crystals are mixed (step), and soak / melting is performed (step). Next, the slide board 22 is moved to mold (step). Then, by cooling (step) and performing molding (step), a source ingot 20 for InP supersaturated solution (batch melt) is obtained. The source ingot 20 is put in a melt box, and soaked during epitaxial growth on the substrate again to make a supersaturated solution. Therefore, the size of the puddle needs to be larger than the batch melt, which, in a typical melt box, determines the lower limit of its width.

According to the present invention, the liquid phase growth melt box 24 serves as a thin film growth solution reservoir and has a width smaller than the width of the batch melt introduction part 25 and the batch melt introduction part 25 in the moving direction of the slide board 22. A contact opening 26 for contacting the semiconductor substrate 21 and the solution is formed. As a result, the area of the contact portion between the semiconductor substrate 21 and the solution is not limited by the size of the batch melt, but within a range that is allowed in consideration of physical properties such as melt viscosity and the degree of wetting between the InP single crystal and the solution. You can make it as small as you want.

A detailed description will be given below. In order to obtain an active layer, which is the second layer for thin film growth, a width smaller than the width of the batch melt introduction part 25 and the width of the batch melt introduction part 25 in the moving direction of the slide board 22, as shown in FIG. An opening 26 for contacting the solution with the semiconductor substrate 21 on which is formed is provided.

Therefore, when manufacturing a semiconductor laser device, in order to form the first layer (p-InP clad layer), the quartz push rod 23 is pushed to move the slide board 22, and first, the p-type InP cladding layer is formed. The -InP solution 31 is brought into contact with the semiconductor substrate 21 to form the p-InP clad layer 42 on the InP substrate 41, as shown in FIG. Next, in order to form the second layer (InGaAsP active layer), an InGaAsP (λg = 1.55 μm) solution 32 is brought into contact with the semiconductor substrate 21 to form a thin InGaAsP active layer 43. Next, in order to form the third layer (n-InP clad layer), the n-InP solution 33 is brought into contact with the semiconductor substrate 21 to form the n-InP clad layer 44. Next, in order to form a fourth layer (n-InGaAsP cap layer), an n-InGaAsP (λg = 1.2 μm) solution 34 is brought into contact with the semiconductor substrate 21 to form an n-InGaAsP cap layer 45.

Here, the lamination process of the first layer, the third layer, and the fourth layer is the same as the conventional one, but only the active layer portion is different. In other words, the first layer (p-InP clad layer), the third layer (n-InP clad layer), and the fourth layer (n-GaAsP cap layer) require a lamination time of several tens of seconds to several minutes, so Do not do so, stay in the solution for a while, and move to the next layer. The second layer is an InGaAsP active layer, and it is necessary to form a thin film. Therefore, the solution portion of the InGaAsP (λg = 1.55 μm) solution is passed at a certain speed. This is often used in epitaxial growth using the step cooling method or the super cooling method. At this time, when growing an InGaAsP layer having a composition with a long oscillation wavelength, the growth rate is high as described above, and therefore the contact time must be very short in order to form a thin epitaxial growth layer. is there.

Further, the present invention is not limited to the above-described embodiments, and various modifications can be made based on the spirit of the present invention, and they are not excluded from the scope of the present invention.

[0017]

[Effect of the device]

 As described above in detail, according to the invention, the conventional batch melt can be used and the contact time between the semiconductor substrate and the solution can be shortened. Thus, passing below it at an appropriate rate allows the formation of thinner DH structures. This is particularly effective for stacking an active layer of an InGaA sP-based long-wave (λg ≧ 1.4 μm) semiconductor laser device having a high epitaxial growth rate and DH embedding (VIPS-LD or the like) using selective growth. In addition, the semiconductor lasers (λg = 1.55LD, etc.) whose active layers are currently formed by a method with a slow epitaxial growth rate, such as the two-phase solution method, can also be switched to the step cooling method, resulting in a steeper hetero It becomes possible to form a bonding interface.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a melt box for liquid phase growth showing an embodiment of the present invention.

FIG. 2 is a view showing manufacturing of a source ingot showing an embodiment of the present invention.

FIG. 3 is a configuration diagram of a semiconductor laser device obtained by applying the present invention.

FIG. 4 is a cross-sectional view of a conventional melt box for liquid phase growth.

FIG. 5 is a configuration diagram of a semiconductor laser device obtained by a conventional technique.

[Explanation of symbols]

20 Source Ingot (Batch Melt) for InP Supersaturated Solution 21 Semiconductor Substrate 22 Slide Board 23 Quartz Push Rod 24 Melt Box for Liquid Phase Growth 25 Batch Melt Introduction Portion 26 Contact Opening Portion 31 p-InP Solution 32 InGaAsP Solution 33 n-InP Solution 34 n -InGaAsP solution 41 InP substrate 42 p-InP clad layer 43 Thin InGaAsP active layer 44 n-InP clad layer 45 n-InGaAsP cap layer

Claims (1)

[Scope of utility model registration request] 1. A melt box for liquid phase growth in which a semiconductor substrate is placed on a slide board, and the slide board is moved to bring the solution into contact with the semiconductor substrate to perform liquid phase epitaxial growth. A batch melt introducing part; and (b) a thin film growth solution reservoir having a contact opening for contacting the solution with the semiconductor substrate, which has a width smaller than the width of the batch melt introducing part in the moving direction of the slide board. Melt box for liquid phase growth.