JPH0654765B2 - Heat treatment container - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat treatment container, and more particularly to a heat treatment container effective for preventing thermal decomposition or thermal deterioration of a material when heat-treating a compound semiconductor.

[Prior Art and its Problems] There are many heat treatment steps in a semiconductor process. A typical example is heat treatment after ion implantation. Since the mechanical properties of most materials become weaker at higher temperatures, careful consideration must be given to careful materials during the heat treatment process.
Particularly in compound semiconductors, stoichiometric defects are likely to occur in the heat treatment step. Stoichiometric defects generated in such processes are often the performance of devices produced with the occurrence of stoichiometric defects in order to significantly reduce the carrier mobility and lifetime, which are the basic properties of semiconductors. Will be low. For example, it is well known that GaAs, which has attracted attention as an integrated circuit material, has a problem in stability of a heat treatment process after ion implantation. Usually, the heat treatment after ion implantation is performed by coating an insulating film such as SiO ₂ or Si ₃ N ₄ , but it is difficult to sufficiently control the insulating film itself or the interface structure between the insulating film and GaAs. Often, microscopically observable defects are observed, and field effect transistors (FET: Field), which are the basic elements of GaAs integrated circuits
Effect Transistor) threshold voltage etc. are not reproducible and the uniformity in the same wafer is not sufficient. From such a situation, a method of performing heat treatment after ion implantation in an As atmosphere in which the vapor pressure is controlled is used. However, although the mirror state of the surface can be relatively retained, the threshold value and the like can be compared with the above reproducibility and uniformity. It does not always meet the requirements. The main cause of these is that the stoichiometric ratio near the surface is insufficiently controlled during heat treatment. In addition to problems such as reproducibility and uniformity, stoichiometric defects are also considered to impair the reliability of fabricated devices, and when heat treating compound semiconductors, prevent the occurrence of stoichiometric defects. Must be considered.

[Object of the Invention]

As described in the prior art and its problems, the object of the present invention is to prevent the occurrence of stoichiometric defects, especially in the case of heat treating a compound semiconductor, and to provide a stable and effective device for manufacturing a high performance and highly reliable device To provide a heat treatment container.

[Structure of Invention]

The heat treatment container of the present invention is provided with an open chamber capable of accommodating a compound semiconductor wafer, a lid container having a fitting portion formed over the entire outer periphery, and at least the open chamber when the lid container is covered. A first space formed so as to accommodate the first space, the first space being in communication with the first space through a pore, and the first space formed so as to house the fitting portion when the lid container is covered. And a container having two spaces.

[Operation and principle of the invention]

Here, GaA, which has received the most attention among compound semiconductors
First, the action and principle of the heat treatment container of the present invention will be described with reference to s materials.
A description will be given with reference to the drawings and FIG. GaAs has attracted attention as an integrated circuit material, and a typical typical heat treatment process is a heat treatment after ion implantation. In the heat treatment step of the compound semiconductor, since the compound semiconductor and the heat treatment atmosphere are generally thermodynamically nonequilibrium, stoichiometric defects occur near the sample surface. Thermodynamically intended heat treatment under equilibrium conditions is the heat treatment in the As atmosphere in which the vapor pressure is controlled as described in the related art and its problems, but the As atmosphere is artificially controlled. It cannot be said that it is close to the mechanical equilibrium condition, and its control is not easy. Basically, it is ideal that the thermodynamic equilibrium condition is automatically established if the temperature is determined. 1st in this invention
The heat treatment is carried out in a container as shown in the figure, and the structure of the container is shown which can be automatically prepared by setting the temperature for heat treatment under conditions close to thermodynamic equilibrium. First
The figure is an example of a container for heat treatment of the present invention, in this case is a cylindrical container, which is shown in a cross-sectional structure, the container 11 and the lid container 12 are made of carbon, and a moat shape dug in the container 11. Groove
A second space is formed by 13 and Ga 13 is formed in this groove 13.
1 and GaAs 132 are prepared and become a Ga solution 14 saturated with As during heat treatment (FIG. 2). Further groove 13
In is placed is B ₂ O ₃ 15, at the time of the heat treatment the B ₂ O ₃ 15
Also melts and covers the Ga solution 14 due to the difference in specific gravity. The lid container 12 has a susceptor portion 17 as an open room in which the heat-treated GaAs substrate 16 is placed. FIG. 2 is a cross-sectional view of the state in which the container 11 is covered with the lid container 12 at a certain temperature of 500 ° C. or higher. In the Ga 131 in the groove 13, GaAs 132 corresponding to the solubility determined only by the temperature is melted to become a Ga solution 14 and B
₂ O ₃ 15 covers it. When the lid container 12 covers the container 11, a tapered fitting portion attached to the lid container 12
18 is set to create at least a clinging state to the molten B ₂ O ₃ 15 described above. By creating the state shown in FIG. 2, the inside of the container 11 is cut off from the outside. The container is sealed with the molten Ga solution 14 and B ₂ O ₃ 15. The inner space of the container is in contact with the Ga solution, which is a saturated solution of As, with many pores 19 formed in the inner wall of the groove 13 of the container 11. Is in thermal equilibrium with the GaAs substrate 16. Further, since the Ga solution 14 is shielded from the atmosphere outside the sealed container by B ₂ O ₃ 15, the dissociation and scattering of As from the Ga solution into the gas phase is extremely small. Incidentally, B ₂ O ₃ is a very famous material as a molten material solution surface sealing to prevent dissociation scattering from the solution during GaAs crystal pulling As to the gas phase, the base material structure through B ₂ O ₃ 15 It dissociates and scatters elements very effectively. That is, by using the container described above, the gas phase inside the enclosed container surrounding the GaAs substrate 16 is in thermal equilibrium with the GaAs substrate 16, and the composition of the gas phase is automatically determined only by the temperature. The stoichiometric ratio of is always determined only by the temperature, and stable heat treatment can be realized.

〔Example〕

An embodiment of the present invention will be described in detail below with reference to the drawings. As shown in FIG. 3, a bottomed cylindrical container 11 made of carbon is placed on the bottom surface of the reaction tube 20. This container 11
A cylindrical outer wall 11A having an inner surface formed in a tapered shape, and a cylindrical inner wall 11B formed in a circular center with the outer wall 11A and lower than the outer wall 11A. The cylindrical inner wall 11B is provided with a plurality of pores 19 at equal intervals along the circumferential direction.
The space between the inner wall 11B and the outer wall 11A communicates with the inner space of the inner wall 11B by 19.

The lid container 12 is housed in the reaction tube 20 in a state of being connected to one end of a quartz piece sealing tube 22 which is movable in the axial direction. On the outer periphery of the bottom surface of the lid container 12, a fitting portion 18 having an outer surface tapered like the outer wall 11A of the container 11 is formed. An open susceptor portion 17 for accommodating the compound semiconductor wafer is formed in a cylindrical portion surrounded by the fitting portion 18. A high frequency coil 21 for heat treatment is arranged on the outer periphery of the bottom surface of the reaction tube 20.

The operation of the present embodiment will be described below by taking the heat treatment after ion implantation of the GaAs material as an example. In order to actually perform the heat treatment, first, as shown in FIG. 3, the container 11 and the lid container 12 are separately arranged in the reaction tube 20, and then 100 H ₂ gas is introduced into the reaction tube 20.
The reaction tube 20 is sufficiently flushed with H ₂ by flowing it at a rate of ml / min. After this, an electric current is passed through the high frequency coil 21 and the container 11
To 800 ° C. At this time, the lid container 12 is the GaAs substrate 16
The container 11 is sufficiently removed from the container 11 in order to keep the temperature below 100 ° C. By heating container 11 to 800 ℃ and keeping it for 30 minutes, G
Solution 14 is fully saturated with As. Then, the current of the high frequency coil 21 is reduced to lower the temperature of the container 11 to 800 ° C. After that, the quartz piece sealing tube 22 is moved from the outside of the reaction tube to quickly cover the lid container 12 on the container 11. This state is shown in FIG. 4, and as described in the operation and principle of the invention, Ga
Since the As substrate 16 is placed in the thermal equilibrium atmosphere in the sealed container determined only by the temperature, the surface state does not change, and stable heat treatment can be performed without the occurrence of stoichiometric defects. That is, stable heat treatment of the compound semiconductor can be performed by using the container described above.

As described above, according to this embodiment, the uniformity of the threshold voltage of the FET in the GaAs wafer can be significantly improved.

It should be noted that the structures of the container 11 and the lid container 12 are not limited to those shown in the embodiments, and the shapes and the like are not limited. The necessary requirement is to have a structure capable of sealing the space between the container 11 and the lid container 12 having a room for containing the material to be heat-treated with the melt, and between the groove 13 for containing the melt made in the container 11 It is sufficient that the pores 19 are formed and at least communicate with the room for containing the material to be heat treated. Further, although carbon is shown as an example of the material of the container 11 and the lid container 12, BN or the like can be adopted, and the material is not essentially limited. Further, as is clear from the above description, the kind of the base material compound semiconductor to be heat treated is not limited, and GaP,
Not to mention InP, it is a vessel for heat treatment applicable to a mixed crystal group such as InGaAsP.

〔The invention's effect〕

By applying the heat treatment container of the present invention, the ion-implanted compound semiconductor wafer can be subjected to stable heat treatment in which the surface state does not change and stoichiometric defects do not occur. In addition, by using the container of the present invention at any time and under any circumstances, it is possible to perform a post-ion implantation heat treatment process with excellent reproducibility that requires almost no operator know-how. Is obtained.

[Brief description of drawings]

1 and 2 are cross-sectional views of a heat treatment container for explaining the principle of operation of the present invention, and FIGS. 3 and 4 are cross-sectional views of an embodiment of the present invention. 11 …… Container 12 …… Lid container 13 …… Groove 14 …… Ga solution 15 …… B ₂ O ₃ 16 …… GaAs substrate 17 …… Susceptor part 18 …… Mating part 19 …… Pore

Claims (1)

[Claims] 1. A lid container having an open chamber capable of accommodating a compound semiconductor wafer, a lid container having a fitting portion formed over the entire outer periphery thereof, and at least the open chamber accommodated when the lid container is covered. A second space formed so as to be capable of being communicated with the first space through a pore and capable of accommodating the fitting portion when the lid container is covered. A container with a space,
A heat treatment container containing.