JPH065614A - Heat treatment device - Google Patents

Abstract

PURPOSE:To simplify the entire structure of a heat treatment device, to cut down the cost of the heat treatment and the cost for heat treatment, and also to make a susceptor small in size. CONSTITUTION:A susceptor 1, having housing space 3 which is closed after a compound semiconductor substrate 11 and a high vapor pressure metal 12 are housed, and a single heat source 2, with which the susceptor 1 is heated up, are provided on the heat treatment device. A through hole 4 communicating with the housing space 3 is formed on the prescribed place on the upper side of the susceptor 1, and a cap 5, with which the through hole is closed, is provided in such a manner that it can be pushed up. On the other hand, the cap 5 is pushed up by the internal pressure of the housing space 3 when the internal pressure exceeds the prescribed value in the course of heat treatment performed on the compound semiconductor substrate 11 by the heat source 2, and the through hole 4 is opened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat treatment apparatus used when heat treating a compound semiconductor substrate.

[0002]

2. Description of the Related Art Conventionally, an operating layer (active layer) in a compound semiconductor device such as GaAsFET is generally formed by ion implantation of Si or the like, and is compared with a compound semiconductor substrate after ion implantation. As a general procedure, heat treatment (annealing) for activating implanted ions is performed. However, when the heat treatment is performed at a high temperature, the surface of the substrate may be decomposed or deteriorated, which may lead to a remarkable deterioration of the device characteristics.

Therefore, in order to prevent such inconvenience from occurring, recently, a heat treatment is carried out after forming a protective insulating film such as a silicon oxide film on the surface of the compound semiconductor substrate (cap annealing). ), Heat treatment is generally performed (capless annealing) in a high-pressure high-vapor-pressure atmosphere without forming any protective insulating film. However, in cap annealing, the activation state of ions and the formation state of surface traps are likely to differ due to the difference in the type and thickness of the protective insulating film, which causes another inconvenience that it is difficult to control the device characteristics. Further, in the capless annealing, for example, an atmosphere gas such as AsHs is used for a compound semiconductor containing As, which is extremely dangerous and a large-scale facility for preventing the leakage. As a result, the equipment cost is increased.

Therefore, as a safe and simple method for avoiding these inconveniences, the susceptor 1 as shown in FIG.
The heat treatment using a heat treatment apparatus provided with 0 has come to be performed. That is, the susceptor 10 included in this heat treatment apparatus is a GaAs substrate 11 which is a compound semiconductor substrate.
And a storage space 13 that is closed after storing the metal As12 that is a high vapor pressure metal serving as an atmosphere source, and each storage portion is provided with a wide partition portion 10a that is raised. Are separated from each other.

In the heat treatment apparatus having the susceptor 10, first, the GaAs substrate 11 and the metal As 12 are stored in the storage space 13 of the susceptor 10, respectively.
Heater 1 which is a heating source capable of temperature control prepared in advance in two sets
One of the four heats the GaAs substrate 11 to the heat treatment temperature required by itself, and the other heater 14 heats the metal As12 to a required vapor pressure, that is, a predetermined pressure required for the heat treatment of the GaAs substrate 11. It is heated to a sublimation temperature at which the atmosphere gas it has is obtained.
Then, the storage space 13 is filled with the atmospheric gas composed of the metal As12, and the GaAs substrate 11
Will be heat treated.

[0006]

By the way, in the heat treatment using the susceptor 10 having the conventional structure,
Since the heating temperatures of the GaAs substrate 11 and the metal As 12 housed in the housing space 13 of the susceptor 10 are different from each other, it is necessary to purposely prepare two sets of heaters 14 and then carry out heating while individually controlling the temperature. I have to. Therefore, not only the entire structure of the heat treatment apparatus becomes complicated, but also the equipment and the heat treatment cost increase. Further, in order to minimize the thermal mutual interference between the GaAs substrate 11 and the metal As 12 that are heated at different temperatures, the space between the susceptor 10 and the storage space 11 of the susceptor 10 is increased, and the wide partition portion 10a is formed. As a result, the entire shape of the susceptor 10 itself becomes large.

The present invention was devised in view of such inconvenience, and it is possible to reduce the cost of the apparatus and the heat treatment while simplifying the overall structure.
It is an object of the present invention to provide a heat treatment apparatus capable of realizing downsizing of a susceptor.

[0008]

In order to achieve such an object, a heat treatment apparatus according to the present invention includes a susceptor having a storage space for storing and closing a compound semiconductor substrate and a high vapor pressure metal. , A single heating source for heating the susceptor, a through hole communicating with the storage space is formed at a predetermined position on the upper side of the susceptor, and a cap body for closing the through hole can be pushed up. On the other hand, the cap body is pushed up by the internal pressure to open the through hole when the internal pressure of the storage space exceeds a predetermined value in the heat treatment process of the compound semiconductor substrate by the heating source. It is characterized by being

[0009]

According to the above structure, the compound semiconductor substrate and the high vapor pressure metal housed in the housing space of the susceptor are both heated by the single heating source to the heat treatment temperature required for the compound semiconductor substrate. At this time, since the sublimation temperature of the high vapor pressure metal is much lower than the heat treatment temperature of the compound semiconductor substrate, the pressure of the atmospheric gas composed of the high vapor pressure metal sublimated by heating at a higher temperature than necessary, that is, this The internal pressure of the storage space filled with the atmospheric gas increases to a pressure equal to or higher than the predetermined pressure required for the heat treatment of the compound semiconductor substrate.

However, the susceptor is formed with a through hole that communicates with the storage space, and the through hole is closed by a cap body that can be pushed up.
When the internal pressure of the storage space exceeds a predetermined value, the cap body is pushed up by the action of the internal pressure, and as a result, the through hole is opened. Therefore, the atmospheric gas filling the storage space of the susceptor is diffused to the outside through the opened through hole, and the internal pressure of the storage space is reduced to a predetermined pressure necessary for heat treatment of the compound semiconductor substrate.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic sectional view of a heat treatment apparatus according to this embodiment. This heat treatment apparatus includes a susceptor 1 used for heat treatment of a compound semiconductor substrate and a heating source for heating the susceptor 1. A single heater 2 is provided. In FIG. 1, parts and portions which are the same as or correspond to those in FIG. 4 showing a conventional example are denoted by the same reference numerals.

The susceptor 1 includes a GaAs substrate 11 which is a compound semiconductor substrate and a metal As1 which is a high vapor pressure metal.
2 and a storage space 3 that is hermetically closed is formed, and each of the storage portions that stores the GaAs substrate 11 and the metal As 12 is a narrow partition formed by rising from the bottom of the storage space 3. It is arranged at a close position separated via the portion 1a. And this susceptor 1
A through hole 4 communicating with the storage space 3 is formed at a predetermined location on the upper side of, for example, a location facing the center of the upper surface of the GaAs substrate 11.

Further, a cap body 5 capable of closing the through hole 4, that is, a cap body 5 in the shape of a round bar with a collar as shown in FIG. It is placed. And this cap body 5
Has a self-weight that is pushed up when the internal pressure of the storage space 3 exceeds a predetermined pressure required for heat treatment of the GaAs substrate 11, and the lower end portion inserted into the through hole 4 has increased sensitivity to pressure. A cut-off portion 5a for forming is formed. Further, an exhaust gas pipe 6 continuous with the through hole 4 itself is connected to the outside of the through hole 4 of the susceptor 1, and the connecting portion of the exhaust gas pipe 6 is thick enough to allow the cap body 5 to move without any inconvenience. It is said that.

Next, the operation and action of the heat treatment apparatus according to this embodiment will be described.

First, Ga implanted with ions such as Si
An As substrate 11 and a metal As12 that is an atmosphere source are housed in a storage space 3 of the susceptor 1, and after the storage space 3 is hermetically closed, a lamp furnace configured by using a halogen lamp is used. The susceptor 1 is placed in another heat treatment furnace (not shown) and then placed. That is, here, the heat treatment furnace functions as the heater 2 which is a single heating source for heating the susceptor 1. Then, by operating this heat treatment furnace, the susceptor 1 is heated until the temperature of the GaAs substrate 11 becomes about 800 to 1000 ° C. which is the heat treatment temperature required.

However, at this time, the metal As12 heated together with the GaAs substrate 11 has the characteristics as shown in the temperature-vapor pressure diagram of FIG.
The metal As12 heated to a high temperature exceeding 0 ° C. sublimes vigorously, and the atmosphere gas composed of this metal As12 is several To which is suitable for the heat treatment of the GaAs substrate 11.
After greatly exceeding the pressure of rr, the storage space 3 is filled with the pressure of several thousand Torr.

However, the susceptor 1 is provided with a through hole 4 which communicates with the storage space 3.
Is closed by the cap body 5, that is, the cap body 5 having its own weight enough to be pushed up by the action of a pressure exceeding a predetermined value required during the heat treatment of the GaAs substrate 11. Then, when the internal pressure of the storage space 3 exceeds the predetermined value due to the filling of the atmospheric gas made of the metal As12, the cap body 5 is pushed up by the action of the internal pressure, and the through hole 4 is opened. become. Therefore, the atmospheric gas filling the storage space 3 of the susceptor 1 is diffused to the outside of the heat treatment furnace through the open through hole 4 and the exhaust gas pipe 6, and the internal pressure of the storage space 3 is transferred to the GaAs substrate 11. It is maintained after being lowered to a suitable number of Torr. The heat treatment of the GaAs substrate 11 under such a condition is performed for several seconds to several tens minutes.

By the way, the atmosphere gas used in this embodiment, that is, the atmosphere gas obtained by sublimation of the metal As12 is highly safe and does not use the dangerous AsHs gas as in the conventional example. Therefore, it is not necessary to implement measures for preventing atmospheric gas leakage as strictly as in the conventional example, and it goes without saying that the equipment cost can be reduced accordingly.

[0020]

As described above, according to the heat treatment apparatus of the present invention, the heat treatment of the compound semiconductor substrate is performed while the susceptor containing the compound semiconductor substrate and the high vapor pressure metal is heated by only a single heating source. As a result, the overall structure of the heat treatment apparatus can be simplified and the cost of the apparatus and the heat treatment can be significantly reduced. Further, since it is not necessary to consider the thermal mutual interference between the compound semiconductor substrate and the high vapor pressure metal, it is possible to obtain the effect that the susceptor can be downsized.

[Brief description of drawings]

FIG. 1 is a sectional view schematically showing a heat treatment apparatus according to the present embodiment.

FIG. 2 is an external perspective view showing a schematic shape of a cap body.

FIG. 3 is a temperature-vapor pressure diagram showing characteristics of metal As.

FIG. 4 is a cross-sectional view showing a simplified heat treatment apparatus according to a conventional example.

[Explanation of symbols]

 1 Susceptor 2 Heater (Heat Source) 3 Storage Space 4 Through Hole 5 Cap Body 11 GaAs Substrate (Compound Semiconductor Substrate) 12 Metal As (High Vapor Pressure Metal)

Claims (1)

[Claims] 1. A susceptor (1) having a storage space (3) for accommodating and closing a compound semiconductor substrate (11) and a high vapor pressure metal (12), and a unit for heating the susceptor (1). A heat source (2) is provided, and a through hole (4) communicating with the storage space (3) is formed at a predetermined position on the upper side of the susceptor (1), and the through hole (4). A cap body (5) for closing the container is placed so that it can be pushed up, while the cap body (5) is arranged in the storage space (3) during the heat treatment process of the compound semiconductor substrate (11) by the heating source (2). The heat treatment apparatus is characterized in that, when the internal pressure exceeds a predetermined value, the internal pressure is pushed up to open the through hole (4).