JPS63265887A - Device for growing crystal in liquid phase - Google Patents

Abstract

PURPOSE:To obtain a device for growing crystal in liquid phase which is capable of growing the activated layer of a thin film with good reproducibility and controllability by constituting material of the part stored with a soln. that is used for growing the activated layer of the thin film succeeding the growth of a cladding layer of the material having thermal conductivity lower than material of the part stored with the other soln. CONSTITUTION:The temp. of the hydrogen atmosphere in the inside of a reaction tube 7 constituted of a quartz pipe is changed along the program of growth temp. shown in a chart by controlling electric source fed to a heater 8. Owning to such temp. reduction, the temp. of a soln. reservoir 2 and the soln. is slowly cooled by mass heat transfer to the hydrogen atmosphere purging the inside of the tube 7, thermal conduction and radiation to the tube 7. Therein when surrounding a soln. used in the case of growing an activated layer II by means of materials 12, 13 having low thermal conductivity, the reduction velocity of temp. of this soln. is lowered in comparison with the other soln. and shown in the dotted line of the chart. Therefore in case t1-t3 are difined as the growth time of a lower cladding layer, the growth time of the activated layer and the growth time of an upper cladding layer respectively, the growth temp. of the above-mentioned respective layers is made to T1-T3 and the growth temp. T21 of the activated layer can be preset independently for the other growth temp.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a liquid phase crystal growth apparatus, and particularly relates to a liquid phase crystal growth apparatus used for liquid phase growth of semiconductor elements with a thin film multilayer structure having different compositions. It is something.

[Conventional technology]

FIG. 3 is a cross-sectional view showing a conventional liquid phase crystal growth apparatus. In the figure, 1 is a substrate holder, the top surface of which is formed of carbon, and the bottom formed by the surface of the substrate holder 1. A constituting solution reservoir 2 is slidably mounted. 3 is the lid of the solution reservoir 2, 4 is the substrate holder 1
5 is a push rod for moving the solution reservoir 2 relative to the substrate holder 1; 6 is an arrow indicating the moving direction of the solution reservoir 2;
8 is a reaction tube constituted by a quartz tube that houses the growth device and holds it in hydrogen; 8 is a heater that controls the temperature. Further, 9°11 is a solution used when growing the lower and upper cladding layers of the semiconductor laser housed in the solution reservoir 2, and 10 is a solution used when growing the active layer of the semiconductor laser housed in the solution reservoir 2. It is a solution that

Next, the operation will be explained. In the liquid phase crystal growth apparatus configured in this manner, the growth apparatus is inserted into the reaction tube 7 with a semiconductor substrate mounted at the processing substrate mounting position 4, and placed in a hydrogen atmosphere. Then, when the substrate holder 1 is moved one step by the push rod 5 at predetermined intervals, the solution 9 comes into contact with the surface of the semiconductor substrate to be processed mounted at the substrate mounting position 4, and the liquid phase crystals of the lower ground layer are brought into contact with the surface of the semiconductor substrate to be processed. Growth takes place. Next, the substrate holder 1 is further moved one step in the direction of the arrow 6 by the push rod 5, and the solution 10 is placed on the semiconductor substrate to be processed mounted at the substrate mounting position 4. The liquid phase crystal growth of the active layer is performed with the solution 10 in contact with the surface. Furthermore, the substrate holder 1 is moved one step in the direction of the arrow 6 by the push rod 5, and the solution 11 is moved to the substrate mounting position 4.
When placed on the semiconductor substrate to be processed mounted on the
The solution 11 comes into contact with the surface of the semiconductor substrate to be processed, and liquid phase crystal growth of the upper cladding layer is performed. On the other hand, the heater 8 uses a controller (not shown) to gradually lower the temperature in the hydrogen atmosphere in each treatment step according to the temperature program shown in FIG. We are growing. In addition,
T+, Tz, and Tz shown in FIG. 4 indicate the lower cladding layer growth temperature, active layer growth temperature, and upper cladding layer growth temperature, respectively, of a semiconductor element having a double heterostructure, and LI+t
z and tz are lower cladding layer growth time and active layer growth time.

The growth time of the upper cladding layer is shown. Of the three layers mentioned above, only the active layer has a thickness of about 0.1 μm, and this layer must be grown with particularly good controllability. On the other hand, one method for growing the active layer with good control is to reduce the cooling rate.

However, in the current growth of double heterostructures, it is necessary to grow a thick lower cladding layer before growing the active layer, so it is necessary to grow the lower cladding layer at a cooling rate above a certain yield. Later, it is necessary to grow the active and sexual layers. As a result, even if an attempt is made to reduce the temperature decreasing rate of the active layer, the temperature will not follow the temperature program because the heat capacities of the substrate holder and solution reservoir are large.

[Problem that the invention seeks to solve]

Because the conventional liquid phase crystal growth apparatus is configured as described above, it is not possible to control the temperature for forming the active layer with high precision, and as a result, the reproducibility and controllability of thin film growth are extremely poor. There was a problem that was getting worse.

This invention has been made to solve the above-mentioned problems, and an object thereof is to provide a liquid phase crystal growth apparatus that can grow a thin active layer with good reproducibility and controllability. .

[Means for Solving the Problems] In the liquid phase crystal growth apparatus according to the present invention, the material of the part for storing the solution used to grow the active layer of the thin film following the growth of the cladding layer is made of a material other than that of another solution. It is made of a material with lower thermal conductivity than the material of the reservoir.

[Function] The liquid phase crystal growth apparatus according to the present invention is characterized in that the thermal conductivity of the material in the part where the solution used to grow the active layer is stored is lower than that of the material in the part where other solutions are stored. Since the solution in the solution reservoir is slowly cooled, the thermal resistance of the part that stores the solution used to grow the active layer becomes larger than other parts. The temperature decreases to a level lower than the set cooling temperature, thereby ensuring a solution temperature condition suitable for growing the active layer with high precision and good reproducibility.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figures and FIG. 2, the same parts as in FIGS. 3 and 4 are denoted by the same symbols, and the explanation thereof will be omitted. In the same figure, 12 is a solution 1o used when growing the active layer.
It is surrounded by a low thermal conductivity material that has a lower thermal conductivity than conventional carbon. As for this low thermal conductivity material 12, the thermal conductivity of the carbon material in other parts is 90.
~130 Kcal/mhr°C, whereas a carbon material with a thermal conductivity of 10 Kcal/mhr°C or less or SiC or the like with a thermal conductivity of 30 Kcal/mhr°C or the like is used. Reference numeral 13 denotes a low thermal conductivity material constituting a portion of the lid 3 of the solution reservoir 2 that faces the portion where the solution 10 used for growing the active layer is stored, and is similar to the low thermal conductivity material 12 described above. , thermal conductivity is 10Kcal/m
Carbon material below hr℃ or thermal conductivity is 30Kcal
/mhr°C or less SiC or the like is used.

The operation will be explained below. First, when the power is turned on, a temperature controller (not shown) controls the power supply to the heater 8 to adjust the hydrogen atmosphere temperature inside the reaction tube 7 made of a quartz tube according to the growth temperature program shown in FIG. change. That is, as shown in FIG. 2, after raising the temperature to a certain level, the temperature is lowered as shown by the solid line. As the temperature is lowered in this way, the temperature of the solution reservoir 2 and the solution gradually decreases due to mass heat transfer 1 with the hydrogen atmosphere purging the inside of the reaction tube 1 and heat conduction and radiation to the reaction tube 7. Let it cool down.

When the solution used for growing the active layer is surrounded by a low thermal conductivity material 12.13, the temperature of this solution decreases faster than other solutions, as shown by the dotted line in Figure 2. It becomes like this. Therefore, t I , t21
．． If t3 is the lower cladding layer growth time, the active layer growth time, and the upper cladding layer growth time, the lower cladding layer growth temperature, the active layer growth temperature, and the upper cladding layer growth temperature of the semiconductor element having a double heterostructure are as follows. From Figure 2, Tl1
T211T3, making it possible to set the active layer growth temperature TZI independently of other growth temperatures.
“It goes without saying that it is necessary to change the solution used in advance to match the rate of decrease in temperature.Furthermore, in the above example, the slide board type liquid phase crystal growth apparatus Although only the case where the present invention is applied has been described, the same effect can be obtained even if it is applied to a liquid phase crystal growth apparatus using a bush outboard method.

〔Effect of the invention〕

As explained above, according to the present invention, since the part of the liquid phase crystal growth apparatus that accommodates the solution for growing the active layer is made of a material with low thermal conductivity, the rate of temperature decrease of the solution is lower than that of other materials. This has the effect of significantly improving the reproducibility and controllability of the active layer since the temperature decrease rate is lower than that of the solution.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a liquid phase crystal growth apparatus according to an embodiment of the present invention, FIG. 2 is a characteristic diagram showing growth temperature program characteristics when the liquid phase crystal growth apparatus shown in FIG. 1 is used, and FIG. The figure is a cross-sectional view showing a conventional liquid phase crystal growth apparatus.
The figure is a characteristic diagram showing a growth temperature program when the liquid phase crystal growth apparatus shown in FIG. 3 is used. 1 is a substrate holder, 2 is a solution reservoir, 3 is a lid, 4 is a substrate mounting position, 5 is a push rod 1.6 is an arrow, 7 is a reaction tube, 8 is a heater, 9, 10.11 is a solution, 1213 is a low heat conductive material. Note that the same reference numerals in the figures indicate the same or equivalent parts. Agent Masuo Oiwa (2 others) 1...Substrate holder 2...Solution reservoir 12.13...Low thermal conductivity member Figure 2

Claims (7)

[Claims] (1) When constructing a semiconductor device composed of multiple thin multilayer films with different compositions by liquid phase growth, by sequentially bringing a dissolved solution into contact with a substrate while gradually lowering the temperature, crystals can be grown due to solubility differences. A liquid phase crystal growth apparatus for precipitation, characterized in that only a specific solution is made of a low thermal conductivity material whose thermal conductivity is lower than that of members constituting parts that accommodate other solutions. (2) The thermal conductivity of the solution reservoir at the operating temperature is 90 to 13.
Claim 1, characterized in that it is made of carbon having a thermal conductivity of 0 Kcal/mhr°C, and carbon having a thermal conductivity of 10 Kcal/mhr°C or less at the operating temperature is used in the part surrounding the specific solution. liquid phase crystal growth equipment. (3) The liquid phase crystal growth apparatus according to claim 1, wherein a portion surrounding a specific solution is made of a material other than carbon, and a portion surrounding other solutions is made of carbon. (4) The thermal conductivity of the solution reservoir at the operating temperature is 90 to 13.
Claim 1 characterized in that it is made of carbon having a thermal conductivity of 0 Kcal/mhr°C and a member having a thermal conductivity of 30 Kcal/mhr°C or less at the operating temperature is used in the part surrounding the specific solution. The liquid phase crystal growth apparatus described above. (5) The thermal conductivity of the solution reservoir at the operating temperature is 90 to 13.
Claim 1, characterized in that it is made of carbon having a thermal conductivity of 0 Kcal/mhr°C, and a SiC member having a thermal conductivity of 30 Kcal/mhr°C or less at the operating temperature is used for the part surrounding the specific solution. The liquid phase crystal growth apparatus described in 2. (6) The solution reservoir that accommodates a specific solution is made of a material other than carbon that has a thermal conductivity of 30 Kcal/mhr°C or less at the operating temperature, and the solution reservoir that accommodates other solutions has a thermal conductivity of 90 to 130 Kcal. 2. The liquid phase crystal growth apparatus according to claim 1, characterized in that the liquid phase crystal growth apparatus is constructed of a member other than carbon, which has a temperature of /mhr°C. (7) The thermal conductivity of the solution reservoir at the operating temperature is 90 to 13.
0Kcal/mhr°C or less, and a member other than carbon having a thermal conductivity of 30Kcal/mhr°C or less at the operating temperature is disposed in a portion surrounding a specific solution. A liquid phase crystal growth apparatus according to scope 1.