JPH0897139A - Method for manufacturing compound semiconductor single crystal and its manufacturing apparatus - Google Patents

Abstract

PURPOSE: To achieve stable crystal growth excellent in yield rate by enabling the temperature distribution adjustment within a furnace to be performed without manual operation, and enabling the temperature distribution with little distribution excellent in reproductivity to be made. CONSTITUTION: The temperature distribution within a high-temperature furnace 1 is measured with the thermocouple of a profiler 8. A personal computer 9 for control where measured temperature distribution is inputted determines the difference between the measured temperature distribution and the objective temperature distribution, and judges whether the difference is in the tolerable range or not. When the difference is not within the tolerable range, the personal computer 9 for control operates the temperature distribution modification data proportionate to the difference. It controls a temperature adjuster 6, according to this operated temperature distribution modification data. The temperature distribution adjusted by this control is measured again, and the control is repeated until the measured temperature distribution becomes the objective temperature distribution. This way, the temperature distribution of a hightemperature furnace is controlled to an objective value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for producing a compound semiconductor single crystal by the boat method, and more particularly to an improved method for adjusting the temperature distribution in a high temperature furnace.

[0002]

2. Description of the Related Art As a method for producing a compound semiconductor single crystal by the boat method, a horizontal Bridgman (HB) method has hitherto been used.
Method, temperature gradient (GF) method, etc. have been proposed, and large and long single crystals with low dislocation have been obtained. GF in Figure 4
The conventional example of the manufacturing apparatus of the compound semiconductor single crystal which implements the method is shown. An electric furnace including a high temperature furnace 1 and a vapor pressure control furnace 2 is provided, and a quartz ampoule 4 on which a raw material and a quartz boat 3 are mounted is installed in the electric furnace. The heater 5 for heating the high-temperature furnace 1 is divided into a plurality of regions along the length of the furnace, and the temperature controller 6 can independently control the temperature in each region.

The production of a single crystal is carried out by adjusting the temperature distribution in the high temperature furnace 1 as shown in FIG. 5 and then uniformly lowering the temperature.
At this time, the temperature distribution is adjusted by inserting a distribution measuring thermocouple 7 into the high temperature furnace 1 as shown in FIG. 4 and causing the temperature distribution measuring profiler 8 to travel inside the high temperature furnace 1 at a constant speed. Record the temperature in the direction with a recorder. When this recording and the desired temperature distribution shape are different, the setting of the temperature controller 7 in each area is changed manually, the measurement is performed again, and this is repeated until the desired temperature distribution shape is obtained.

[0004]

However, in the above-mentioned prior art, the temperature distribution of the high temperature furnace is adjusted by a person who judges the difference between the recorded measurement result and the desired temperature distribution shape, and the temperature is adjusted based on experience. Since the setting of the adjuster had to be adjusted, there were the following drawbacks.

(1) A person must be present during temperature adjustment, which is complicated and causes a large loss in time. (2) The adjustment of the temperature is based on the experience of the measurers, and the variation among the measurers becomes large.

(3) Due to the above variation, abnormal crystal growth occurs, which greatly affects the yield and quality.

The object of the present invention is to solve the above-mentioned drawbacks of the prior art, to adjust the temperature distribution in the furnace without human labor, and to form a temperature distribution with good reproducibility and little variation. It is an object of the present invention to provide a method for producing a compound semiconductor single crystal capable of obtaining stable crystal growth with good yield.

Another object of the present invention is to provide an apparatus for producing a compound semiconductor single crystal capable of accurately and automatically correcting the temperature distribution in the furnace with a simple structure of providing a calculation means and a control means. Especially.

[0009]

A method for producing a compound semiconductor single crystal according to the present invention comprises: controlling a temperature controller connected to each of a plurality of heaters divided along a high-temperature furnace to control the temperature inside the high-temperature furnace. In the method for producing a compound semiconductor single crystal by the boat method, which comprises a step of forming a predetermined temperature distribution, in adjusting the temperature distribution, the temperature distribution of the high temperature furnace is measured, and the measured temperature distribution and the target temperature are measured. It is determined whether the difference from the distribution is within the allowable range, and if it is not within the allowable range, temperature distribution correction data proportional to the difference is calculated, and the temperature controller is adjusted according to the temperature distribution correction data. Is to control.

The apparatus for producing a compound semiconductor single crystal according to the present invention comprises a high temperature furnace, a temperature controller for adjusting the temperature of each of the heaters divided along the high temperature furnace, and a measurement for measuring the temperature distribution of the high temperature furnace. And a temperature setting means for setting a target temperature distribution of a high temperature furnace, a temperature distribution correction data calculating means, and a control means for controlling the temperature controller, the manufacturing apparatus for a compound semiconductor single crystal, comprising: The calculation means inputs the measured temperature distribution of the high temperature furnace measured by the measuring device, and when the difference between the measured temperature distribution and the target temperature distribution set by the temperature setting means is not within the allowable range, A value proportional to the difference is output as the temperature distribution correction data, and the control means controls the temperature controller based on the temperature distribution correction data.

[0011]

[Operation] The temperature distribution in the high temperature furnace is measured by the measuring device. The arithmetic means, to which the measured measured temperature distribution is input, finds the difference between the measured temperature distribution and the target temperature distribution preset by the temperature setting means, and determines whether the difference is within the allowable range. .

If the difference is within the allowable range,
The temperature distribution is not corrected because the measured temperature distribution is within the target temperature distribution. If the difference is not within the allowable range, the calculating means calculates the temperature distribution correction data proportional to the difference. The control means to which the calculated temperature distribution correction data is input controls the temperature controller according to the temperature distribution correction data.

The temperature distribution adjusted by this control is measured again, and the above control is repeated until the measured temperature distribution reaches the target temperature distribution. In this way, the temperature distribution of the high temperature furnace is automatically controlled to the target value.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the method and apparatus for manufacturing a compound semiconductor single crystal of the present invention will be described below with reference to the drawings. FIG. 1 shows an apparatus for producing a compound semiconductor single crystal according to this example. The manufacturing apparatus has an electric furnace including a high temperature furnace 1 and a vapor pressure control furnace 2, and a quartz ampoule 4 on which a raw material and a quartz boat 3 are mounted is installed in the electric furnace. The heater 5 for heating the high temperature furnace 1 is divided into a plurality of regions along the furnace length,
In each area, the temperature controller 6 (# 1, # 2, ... #n) can independently control the temperature.

Further, a temperature distribution measuring profiler 8 for measuring the temperature distribution in the high temperature furnace 1 is provided, and the thermocouple 7 for measuring the distribution is inserted in the high temperature furnace 1, and in the furnace length direction at a constant speed. By traveling, the temperature in the furnace length direction can be detected. The profiler 8 is controlled by a control personal computer 9 described later.
The control personal computer 9 is a temperature setting means for setting a target temperature distribution of the high temperature furnace, a temperature distribution correction data calculating means, and a control means for controlling the temperature controller 6.
Is provided. The profiler 8 for temperature distribution measurement and the temperature controller 6 are GP-IB (General Purpo).
It is connected to the control personal computer 9 via an interface such as a se-interface bus). The temperature setting means may be externally attached to the control personal computer.

When the measured temperature distribution of the high temperature furnace 1 measured by the temperature distribution measurement profiler 8 is input to the control personal computer 9 and the difference between the measured temperature distribution and the target temperature distribution is not within the allowable range, A value proportional to the difference is output as temperature distribution correction data to each temperature controller 6, and the temperature controller is controlled based on the temperature distribution correction data.

Next, the function of the manufacturing apparatus will be described with reference to the flowchart of FIG. When in-furnace temperature distribution measurement is started by the temperature distribution measurement profiler 8 that has been operated based on a command from the control personal computer 9, the temperature distribution measurement value is obtained every time the thermocouple moves a fixed distance or a fixed time elapses. Is transmitted to the control personal computer 9, is recorded, and is displayed on the personal computer screen as shown in FIG. 3 (step 201).

At this time, the measurement points are set to a plurality of areas A, B, C.
Can be divided into two areas, and a linear approximation is performed for each area from the measurement points by the least squares method, and the inclination is obtained (step 202). In FIG. 3, black circles are sampling data, a chain line is a measured value, and a straight line is an approximate value. The target inclination and its allowable range for each area are set in advance by the control personal computer 9. The difference between the target value and the measured value is calculated (step 203), and the quality of the temperature distribution shape is determined based on the difference (step 204).

When the determination is negative, the control personal computer 9 calculates temperature distribution correction data proportional to the difference, and the temperature controller 6 is controlled according to the temperature distribution correction data to adjust each temperature. The set temperature of the vessel 6 is corrected (step 205).

After the above measurement and correction of the set temperature are repeated to obtain the temperature distribution shape of the target inclination, the temperature of each heater is gradually lowered, and the temperature inside each boat is gradually lowered from the seed crystal side placed at one end of the boat. Crystallize the melt.

As described above, according to this embodiment, the conventional profiler and the temperature controller of each area are connected to the control personal computer, and the temperature distribution measurement result is recorded on the personal computer.
Since the calculation is performed in the personal computer and the control is performed according to the calculation result, the desired temperature distribution can be automatically adjusted without manpower.

Therefore, during temperature adjustment, unattended operation eliminates time loss, and since temperature adjustment is computer-based, there is no variability.
Since the crystal growth is performed normally, the yield and quality are greatly improved.

[0023]

According to the method of the present invention, the temperature distribution in the furnace can be adjusted without human labor, and the temperature distribution can be formed with good reproducibility and with little variation. As a result, stable crystals with good yield can be obtained. Growth is obtained.

According to the apparatus of the present invention, the temperature distribution in the furnace can be corrected accurately and automatically with a simple structure in which the calculation means and the control means are provided.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a manufacturing apparatus for carrying out a method for manufacturing a compound semiconductor single crystal according to the present invention.

FIG. 2 is an explanatory diagram for obtaining an approximate value of a measured temperature in a high temperature furnace of this embodiment.

FIG. 3 is a flowchart illustrating automatic temperature adjustment of the manufacturing apparatus according to the present embodiment.

FIG. 4 is a schematic configuration diagram of an apparatus for producing a compound semiconductor single crystal of a conventional example.

FIG. 5 is an explanatory view showing a conventional temperature distribution measurement in a furnace.

[Explanation of Codes] 1 high temperature furnace 2 vapor pressure control furnace 3 quartz boat 4 quartz ampoule 5 heater 6 temperature controller 7 thermocouple for distribution measurement 8 profiler (measurement device) for temperature distribution measurement 9 control PC (temperature setting means, Computing unit, control means)

Claims (2)

[Claims] 1. A compound by the boat method, which comprises a step of forming a predetermined temperature distribution in a high temperature furnace by controlling each temperature controller connected to each of a plurality of heaters divided along the high temperature furnace. In the method of manufacturing a semiconductor single crystal, when adjusting the temperature distribution, the temperature distribution of the high temperature furnace is measured, and it is determined whether the difference between the measured temperature distribution and the target temperature distribution is within the allowable range. A method for producing a compound semiconductor single crystal, wherein temperature distribution correction data proportional to the difference is calculated when the temperature does not fall within the allowable range, and the temperature controller is controlled according to the temperature distribution correction data. 2. A high temperature furnace, a temperature controller for adjusting each temperature of a heater divided into a plurality of parts along the high temperature furnace, a measuring device for measuring a temperature distribution of the high temperature furnace, and a target temperature distribution of the high temperature furnace. A compound semiconductor single crystal manufacturing apparatus comprising temperature setting means for setting, temperature distribution correction data calculating means, and control means for controlling the temperature controller, wherein the calculating means comprises:
When the measured temperature distribution of the high temperature furnace measured by the measuring device is input, and the difference between the measured temperature distribution and the target temperature distribution set by the temperature setting means is not within the allowable range,
A value proportional to the difference is output as temperature distribution correction data, and the control means controls the temperature controller based on the temperature distribution correction data. Manufacturing equipment.