JPH01264990A - Method of refinning ii-vi compound semiconductor, production of ii-vi compound semiconductor single crystal and production of semiconductor light emitting element formed by using semiconductor single crystal obtained by the same method as substrate - Google Patents

Abstract

PURPOSE:To obtain the blue light emitting element having excellent light emitting efficiency and light emitting characteristics by disposing a II-VI compd. semiconductor in the high-temp. part in a sealing tube provided with a temp. difference and transporting the impurities contained therein to the low-temp. part in the sealing tube, thereby extremely easily executing refining and enabling gettering of various impurities. CONSTITUTION:The II-VI compd. semiconductor (e.g.: ZnSe polycrystal) which is a raw material to be refined and at least one 13 selected from Zn, chalcogen element (e.g.; Se) and halogen element (e.g. I) which forms the atmosphere in the sealing tube and is the transport body of the impurities in the raw material 12 are sealed into the bottom of the sealing tube 11 formed of a heat resistant material (e.g.; quartz) and after the inside of the tube is evacuated to about 10<-6>Torr pressure, the top part of the tube 11 is hermetically sealed. This tube 11 is then disposed in the heating furnace in such a manner that the bottom of the tube is positioned in the high-temp. part of the heating furnace and the top part in the low-heating part to provide the temp. difference in the tube 11. The refining is thus executed by transmitting and settling the impurities such as Cu, Al, and Cr in the raw material 12 to the low-temp. part by the transport body 13.

Description

[Detailed description of the invention] [Object of the invention] (Industrial application field) The present invention provides a method for manufacturing n-VI group compound semiconductor, ■-VI
The present invention relates to a method for producing a group compound semiconductor single crystal, and a heat treatment method for high purification of an n-VI group compound semiconductor, which is particularly applied to blue light emitting devices, single crystallization of the crystal, and the use of this semi-shaped plate. The present invention relates to a method for manufacturing a semiconductor light emitting device.

(Prior Art) Semiconductor light emitting devices using compound semiconductor materials and having a light emitting range ranging from red to green are being mass produced, and development is underway to further improve the brightness. However, a satisfactory manufacturing technology has not yet been provided for a blue light-emitting element that emits blue light in the visible region.

In order to manufacture blue light emitting devices, it is necessary that the forbidden band width of the semiconductor material exceeds 2.6 to 3.7 eV, and recently, ■-■ group compound semiconductors have attracted attention as semiconductors that satisfy this requirement. It started to be done.

Among these, zinc sulfide (ZnS), zinc selenide (ZnSe), and their mixed crystals (ZnSSe), which have a forbidden band width in the range of 2.6 to 3.7 eV, are considered promising. Hereinafter, the above materials will be collectively referred to as zinc sulfide selenide (ZnSxSe
, 4: O≦8≦1). and,
The single crystal growth method includes, for example, a high-pressure melting method known as a delivery growth method under high-temperature and high-pressure conditions, such as the Bridgman method, the Tamman method, and the sealed tube chemical transport method.

There are methods such as sublimation. According to the above method, it is also possible to obtain a single crystal with a relatively large diameter.

However, the raw materials used for growing the single crystal are powdery,
Or, there are many polycrystalline bodies with irregular shapes. These polycrystals contain large amounts of impurities such as copper. That is, - for the example raw material, the content is i PPm, AQ, Si: 0
．． 5. Cu, Cr: 0.3. Mg: 0.
1 was measured. For this reason, single crystals made from such raw materials naturally inherit impurities, making it impossible to obtain crystals that are satisfactory for use. In addition, impurities have a complicated relationship with lattice defects, etc., and there are limitations to constructing light emitting devices using this crystal. Furthermore, there are no detailed reports on the extraction of impurities from these raw materials in advance.

(Problem to be Solved by the Invention) As mentioned in the above conventional example, the compound semiconductor crystal for the light emitting element contains a large amount of impurities such as copper, aluminum, magnesium, etc. Single crystals made as ZnS and Zn5e also have poor purity, and have problems such as difficulty in controlling electrical resistance and conductivity type, unlike single crystals such as ZnS and Zn5e. In addition, there is Z in the single crystal.
There was a problem in that the generation of n-vacancies and the like was observed, and the light-emitting characteristics were inhibited.

This has been a major obstacle in realizing blue light emitting devices with superior performance.

Furthermore, in the conventional method described above, since the crystallization is carried out in a sealed tube, thermal distortion from the sealed tube and Zn5e on the inner wall of the sealed tube may occur.
Due to its "wettability" with the FA liquid, single crystals contain many twin crystals and have the problem of solidification. There are no reports of impurities being extracted in advance from these raw materials.

When producing a ZnSSe alloy, there are problems in that single crystallization is difficult due to S segregation, and the S concentration is unevenly distributed. Furthermore, single crystals produced by the vertical Bridgman method contain many twin crystals and have low purity.

The present invention was made in view of the above-mentioned conventional problems, and is intended to produce high-quality n-VI group compound semiconductor crystals.
It is an object of the present invention to provide an improved method for purifying and single crystallizing a group I-VI compound semiconductor, and a method for manufacturing a light emitting device using this semiconductor crystal substrate.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides a method for purifying a II-VI group compound semiconductor, ■-■
The present invention relates to a method for manufacturing a group compound semiconductor single crystal, and a method for manufacturing a semiconductor light emitting device using a semiconductor single crystal substrate manufactured using the same. In other words, a sealed tube is used to form a high-temperature part and a low-temperature part, and a compound semiconductor is placed in at least one of these to specify the atmosphere of the sealed tube, and the temperature difference is used to eliminate impurities. Perform processing and single crystallization.

First, the first invention is to package a [-VI group compound semiconductor] in a high-temperature part of a sealed tube with a temperature difference for refining compound semiconductors, and to remove impurities in the compound semiconductor to a low-temperature part of the sealed tube. The present invention provides a method for improving the purity of the II-VI group compound semiconductor by transporting the compound semiconductor.

The second invention, which is a modification of the first invention, resides in a method in which the inside of the sealed tube is made into a mixed atmosphere of a group Ⅰ element, a group ① element, or one of the above homologous elements and a halogen element.

The third invention is to purify a II-VI group compound semiconductor using a sealed tube, by disposing a ■-■ group compound semiconductor in a high-temperature part and an impurity adsorbent in a low-temperature part of the sealed tube with a temperature difference. The fourth invention is a method for improving purity by transporting impurities in a compound semiconductor to a low-temperature part in a sealed tube.6 The fourth invention is a method for improving purity by transporting impurities in a compound semiconductor to a low-temperature part in a sealed tube. Part n-VI
This method involves disposing impurity adsorbents in respective low-temperature parts of group compound semiconductors, transporting impurities within the compound semiconductors to the low-temperature part of a sealed tube, improving the purity, and converting them into single crystals. A fifth invention, which is a modification of the fourth invention, resides in a method in which the inside of the sealed tube is made into an atmosphere of a mixture of a group Ⅰ element, a group ① element, or one of the above homologous elements and a halogen element.

The sixth invention is to produce a compound semiconductor using a sealed tube, and to grow a single crystal by placing an n-VII compound semiconductor in a high-temperature part and a single crystal of the same type in a low-temperature part in a sealed tube with a temperature difference. The seventh invention, which is a method for manufacturing a compound semiconductor using a sealed tube, is a method for manufacturing a compound semiconductor using a sealed tube.
- 5 polycrystals of group II compound semiconductors and single crystals of the same type are placed in the low temperature section, and the inside of this sealed tube is filled with group II or VI compound semiconductors.
The eighth invention resides in a method for growing a single crystal in a mixed atmosphere of group elements and halogen elements.6 The eighth invention resides in a method for growing a single crystal in a mixed atmosphere of group elements and halogen elements.
VII in the melt of Group II elements that constitute the compound semiconductor.
-VII A method of arranging a polycrystalline compound semiconductor, raising the temperature to a predetermined temperature, and converting the polycrystalline body into a single crystal by solid phase growth.

A ninth invention is a method for producing a II-VII compound semiconductor single crystal, which comprises melting a II-VI group compound semiconductor material from one end at a predetermined temperature and sequentially transferring the melted portion to the other end of the material to achieve single crystallization. , a step of assimilating and forming a polycrystal in a first sealed tube, and placing the fixed crystal in a second sealed tube having a larger diameter than the first sealed tube so as to reduce the contact area with the inner wall. The method is to transfer the crystal, reseal it, and perform a heat treatment at a temperature lower than the melting temperature of the II-VI group compound semiconductor crystal to form a single crystal. A tenth invention, which is a modification of the ninth invention, resides in a method in which the heat treatment is carried out in the second sealed tube by arranging an impurity-adsorbing crystal in the low-temperature part. The 11th invention, which is a modification of the 10th invention, resides in a method in which the heat treatment performed in the second sealed tube is performed by enclosing an excessive amount of a group Ⅰ element, a group Ⅰ element, or a halogen element.

The twelfth invention is to manufacture a compound semiconductor using a sealed tube, in which a semi-single crystal of a group II-VI compound is placed in a high-temperature part of the sealed tube with a temperature difference, and a single crystal of the same type is placed in a low-temperature part. There is a method in which single crystal growth is performed by arranging the elements and creating a mixed atmosphere of a group II or group VI element and a halogen element in the sealed tube.

The 13th invention provides a temperature difference in a sealed tube, places a polycrystalline body of an n-VII compound semiconductor in a melt of a group II element constituting the polycrystalline body in a high-temperature part of the sealed tube, and performs solid phase growth. II-V
A method for manufacturing a semiconductor light-emitting device includes forming a II compound single-crystal substrate, laminating an epitaxial layer of the same type on the single-crystal substrate, and using this epitaxial layer as a light-emitting layer.

The fourteenth invention provides a high temperature section in a sealed tube with a temperature difference.
A crystal of a group II compound semi-solid and a single crystal of the same type are respectively placed in a low temperature section, and the single crystal is grown in a mixed atmosphere of a group II or group VI element and a halogen element in the sealed tube. Forming a VII compound semiconductor single crystal substrate, forming an epitaxial layer of the same type on this crystal substrate,
The present invention relates to a method of manufacturing a semiconductor light emitting device using an epitaxial layer as a light emitting layer.

A fifteenth invention resides in a method for manufacturing a semi-calyx light-emitting device according to any one of the thirteenth or fourteenth inventions, characterized in that the light-emitting layer is formed by organometallic vapor phase epitaxy.

A 16th invention is a method for manufacturing a semiconductor light emitting device according to any one of the 13th and 14th inventions, characterized in that the light emitting layer is formed by liquid phase growth using at least one of its constituent elements. It is in.

(Function) The present invention aims at high purity by extracting impurities contained in raw materials in the production of II-VII compound semiconductor single crystals used in blue light emitting devices, by providing a temperature difference in a sealed tube. Based on the idea of transporting impurities from the object placed in a high-temperature section to a low-temperature section, high purity is achieved by developing the atmosphere inside the sealed tube, impurity transporter, impurity adsorbent, etc.

Further, a II-VI group compound semiconductor polycrystal is placed in a melt of a group II element constituting it in a high-temperature part of a sealed tube provided with a temperature difference, and single crystallization is achieved by solid phase growth.

Furthermore, the II-VI group compound semiconductor crystal produced in the first sealed tube containing a large number of twins based on the above is separately placed in a second sealed tube having a larger diameter with a contact area with the inner wall of the second sealed tube. By enclosing the semiconductor in such a way that the
A large single crystal with few defects can be obtained.

Next, a crystal layer of the same type is laminated on the crystal substrate manufactured based on the above, and a light emitting junction is formed using this crystal layer as a light emitting layer, thereby obtaining current-voltage characteristics with good device characteristics. .

(Example) Examples of the first and second inventions will be described below with reference to the drawings.

FIG. 1 shows a sectional view of the sealed tube used in the first to third embodiments of the invention and its internal arrangement. As shown in FIG. 1, polycrystalline Zn5e, which is an example of the raw material 12 to be refined, is placed in a sealed tube 11 made of a heat-resistant material such as quartz, and an atmosphere inside the sealed tube is formed while impurities in the raw material are removed. At least one selected from Zn, a chalcogen element, particularly Se, and a halogen element, particularly iodine, which is a transporter 13, is enclosed, and 10
-' Evacuate the tube to a pressure of about 100 torr and melt-seal the top of the sealed tube. The savior's sealed tube 11 has the bottom part where the raw material I2 and the transporter 13 are placed in the high temperature part of the heating furnace, and the top part in the low temperature part of the heating furnace.
Apply a heat treatment that lasts for a week. This heat treatment is carried out in a heating furnace with a temperature gradient shown in Figure 2, with a high temperature of 850°C, for example.
The temperature of the low temperature part is 840°C, for example.

By acting like a savior, raw material 12 polycrystalline Z
Impurities such as Cu, AQ, and Cr in n5e are transporter 1
3, it is transported to the low-temperature area and deposited. In this heat treatment, the sealed tube 11 has a diameter of 20 mm and a length of 50 mm, and 50 g of polycrystalline Zn5e 12 as a raw material and Zn1 as an impurity transporter are added to the sealed tube 11.
The high temperature part is 850℃ and the low temperature part is 840℃.
It was applied at different temperature ranges. In this way, the impurity concentration of the raw material and each impurity after it has been subjected to the heat treatment is determined by ICP (
The results of the analysis using the injected coupled plasma method are shown in Table 1 below.

As shown in Table 1, heat treatment significantly improved the purity of raw materials, and was particularly effective in extracting heavy metals such as Cr and Cu.

Furthermore, as an atmosphere, in addition to the above-mentioned Zn, the already mentioned S
e, a halogen element, and a mixed atmosphere of Zn and a halogen element, or a mixed atmosphere of Se and a halogen element in the sealed tube, and it is possible to adsorb impurities suitable for each atmosphere.

Next, embodiments of the fourth and fifth inventions will be described with reference to FIG. FIG. 3 shows a sectional view of the sealed tube used in this example and its internal arrangement. As shown in FIG. 3, polycrystalline Zn5e, which is an example of the raw material 12 to be refined, is placed in a sealed tube 21 made of a heat-resistant material such as quartz, and an atmosphere inside the sealed tube is formed while impurities in the raw material are removed. Transport body 13
At least one selected from Zn, a chalcogen element, particularly Se, and a halogen element, for example, iodine, are placed at the bottom, and polycrystalline Zn5e, which is an example of an adsorbent 22, is placed in this seal to adsorb the transported impurities. It is stored in the constriction 21a formed at the top of the tube, and the inside of the sealed tube 21 is 10-'
Evacuate to about Torr and seal the top. The sealed tube 21 configured like a savior has its bottom part where the raw material 12 and transporter 13 are placed in the high temperature part of the heating furnace, and its top part in the low temperature part of the heating furnace. 2
Heat treatment is performed for a week. This heat treatment is carried out in a heating furnace with a temperature gradient shown in Figure 2, with a high temperature of 850°C, for example.
The temperature of the low temperature part is 840°C, for example.

Cu in polycrystalline Zn5e as raw material 12 as a savior.

Impurities such as AQ and Cr are transported by the transporter 13 to the single crystal Zn5e of the adsorbent 22 placed in the low-temperature part, and are adsorbed thereon.

In the second process, the sealed tube 21 has a diameter of 20 mm and a length of 50 mm.

To this, 50g of polycrystalline Zn5e as raw material 12, transporter 1
10111g of Zn of 3, single crystal Zn5e of adsorbent 22
The raw material and the carrier were heated to a high temperature of 850°C.
, the adsorbent was applied with a temperature difference of 840°C. The results of analyzing the impurity concentrations of the raw materials and each of them after the heat treatment using the ICP method are as follows.
As shown in the table, a significant reduction in heavy metals such as Cu and Cr was observed. Furthermore, changes in the impurity concentration in the adsorbent 22 were investigated by the above treatment, and the results shown in Table 3 were obtained.

Margin below As shown in Table 3, the concentration of impurities in the adsorbent 22 shows a remarkable increase, which together with the results in Table 2 means that the impurities contained in the raw material 12 are transferred to the adsorbent by the transporter 13. 2
It is clear that the sample was transported to and adsorbed by 2.

Note that this invention is not limited to the above-mentioned embodiments,
In addition to Zn, the atmosphere includes Si as already mentioned.

A mixed atmosphere of Zn and a halogen element, or a mixed atmosphere of Ss and a halogen element is suitable, and impurities suitable for each atmosphere can be adsorbed.

In addition, the impurity adsorbent described in (g) is
Compatible with compound semiconductors of the same type as Group VI compound semiconductors.

Next, an embodiment of the sixth invention and the seventh invention will be described with reference to FIGS. 4 and 5.

FIG. 4 shows a sectional view of the sealed tube used in one embodiment and its internal arrangement. As shown in FIG. 4, polycrystalline Zn5e as an example of the purified raw material 12 and chemical transporters 13 such as Zn and iodine are placed at the bottom of a sealed tube 21 made of a heat-resistant material such as quartz. In addition, the constriction 2 at the top of the sealed tube 21
Seed crystals 14 of single-crystal Zn5e are respectively placed in 1a. Then, the bottom part of the sealed tube 21 is placed in the high temperature part of the heating furnace, and the top part is placed in the low temperature part of the heating furnace, and in this state, for example, about two weeks pass.This crystal growth is performed at the temperature shown in FIG. In a distributed heating furnace, the temperature of the high temperature part is 850℃, for example.
The Zn5e single crystal grown body 24 was grown at a low temperature part temperature of 840° C. as an example, and was grown into a seed crystal 14 as shown in FIG.
was gotten.

The sealed tube 21 of Example L was formed to have a diameter of 20+ m and a length of 50 m, and the raw material polycrystalline Zn5
10g of a, 50mH of iodine, and 1.2cm of Zn are placed at the bottom, and the single crystal Zn5e of the seed crystal 14 is placed at the constriction part 2 at the top.
1a, the inside of the sealed tube is evacuated to about 10-' Torr to manufacture the semiconductor crystal.

Further, the growth atmosphere may be a mixed atmosphere of Zn or Se, which is an example of a II-VI group compound, and a halogen element. Furthermore, the method is characterized in that the amount of Zn sealed in order to form the growth atmosphere is set to a molar fraction of 172 or less of the halogen element simultaneously sealed.

Regarding the above, a comparison was made using light absorption and photoluminescence between a crystal obtained by a conventional chemical transport method using only iodine of single crystal Zn5e and a crystal obtained by an example of doping with iodine and Zn. . first,
From the comparative data of light absorption shown in Figure 6, it is clear that the results obtained with the present invention have high transmittance at short wavelengths (~47oIJra), little absorption due to impurities, and significantly higher purity. It is. Next, in Figure 7, 325 nm H
The results of room temperature photoluminescence spectra of i-Cd laser light excitation are shown. Compared to iodine alone, this photoluminescence property showed that the SA emission intensity near 580 nm was suppressed, and the blue emission near 470 nm appeared strongly. Thus, the effect of doping Zn (or Se) at the same time as iodine is clear, and a low resistance n-type crystal suitable for a blue light emitting device was obtained.

Next, regarding the crystal growth rate, as shown in Figure 8,
By setting the molar ratio of Zn to the amount of halogen element (iodine) to be simultaneously encapsulated at a molar ratio of 172 or less, a product with excellent characteristics was obtained.

Although Zn5e is used as an example in the embodiment, it goes without saying that similar effects can be applied to other II-VI group compound semiconductor materials such as ZnS, ZnTe, CdSe, and CdTe.

Next, an embodiment of the eighth invention will be described with reference to FIGS. 9 to 11.

As shown in FIGS. 9(a) and 9(b), polycrystalline Zn5e22, which is an example of an n-vi group compound semiconductor, is placed in the high temperature part of the lower part of the ampoule 11 in Zn at 850-1100°C for 20 minutes.
After heat treatment for ~10,000 hours, nearly single crystallization is achieved. FIG. 9(b) shows single crystal Zn5e32. The temperature gradient between the high-temperature part and the low-temperature part of the ampoule is maintained at at least 10°C.

Next, by adding an example of AQ as a third impurity to the Zn and allowing it to diffuse and grow into crystals such as Zn5e and ZnSSe, the electrical resistance value of these crystals can be reduced.

In addition, when adding active impurities such as AQ, as shown in FIG. It is preferable to use a crucible 16 and perform the heat treatment in this crucible.

Next, in the case shown in FIGS. 11(a) and 11(b), the support member 17 of the crystal is locked on the inner surface of the ampoule 21, and the ampoule is turned upside down as shown in FIG. 11(b) during cooling.
This is characterized by separating the single crystal 42 and the single crystal 42. Note that the support member 17 for the crystal body may be inserted using the "necked part" 21a of the ampoule 21.

According to this example, (υ a high-purity single crystal can be easily grown in solid phase, ■ it is possible to align defects on the surface in one direction, (3)
) low resistance can be obtained, (4) impurities can be stably doped, ■ the strain of the solidified film caused by solidification of Zn, for example, is not applied to the single crystal, so the characteristics of the single crystal are improved, etc. There are advantages.

Next, embodiments of the ninth to eleventh inventions will be described with reference to FIGS. 12 to 18.

FIG. 12 shows a sectional view of the sealed tube and its internal arrangement used in the first embodiment of the ninth to eleventh aspects of the invention. The sealed tube 11 shown in FIG. 12 is made of a heat-resistant material such as quartz, and is made of Zn which has been manufactured in advance by the Bridgman method and has been solidified containing a large number of twin crystals.
The Zn5e single crystal body 52 is housed in a sealed tube having a larger diameter than the sealed tube used to manufacture the Zn5e single crystal body 52. That is, when the sealed tube used to manufacture the Zn5e single crystal body 52 has a diameter of 20 mm, for example, the sealed tube 11 has a diameter of 50 nyn to reduce the contact area between the single crystal body 52 and the inner wall of the sealed tube. Let them do it. In addition, this sealed tube 11, together with the Zn5e single crystal 52, forms the atmosphere inside the sealed tube and contains the Zn5e used in the above embodiment.
At least one selected from Zn, a chalcogen element, particularly Se, and a halogen element, such as iodine, which is an impurity transporter 13 in the 5e single crystal, and a Zn5e single crystal 14 that adsorbs impurities transported by the impurity transporter 13. is sealed and the top of the sealed tube is melt-sealed by evacuation to about 10-'' Torr. The top part is placed in the high-temperature part of the heating furnace, and the top part is placed in the low-temperature part of the heating furnace, and heat treatment is performed in this state for about two weeks, for example.This heat treatment is performed in a heating furnace with the temperature gradient shown in FIG. is applied at an example of 850°C, and the low temperature part temperature is applied at an example of 840°C.As a result, C in crystalline Zn5e52, which is a raw material, is
Impurities such as u, Ax, and Cr are transported to the low temperature part by the transporter 13 and deposited therein.

The above heat treatment is applied to the sealed tube 11, which has a diameter of 50 m and a length of 1 as an example.
A 50 on quartz ampoule was used, and Zn5 was added to the bottom of it.
e 150g of single crystal 52, 10g of Zn as transporter 13
After each was placed inside and vacuum-sealed as described above, it was placed in an electric furnace with a temperature distribution shown in FIG. 2 and heat-treated.

After two weeks of heat treatment, more than 70% of the twins in the extracted Zn5e single crystal had disappeared, and it was confirmed that the Zn5e single crystal was of high quality.

The atmosphere for the heat treatment during sampling is 10 atmospheres or more. Further, the heat treatment temperature is selected and set within the range of 700°C to 1250°C. Furthermore, although the case where the temperature difference between the high temperature part and the low temperature part is 10°C has been exemplified, the present invention is not limited to this, and is effective as long as it is within 100°C.

Next, the second embodiment shown in FIG. 13 uses a quartz ampoule with a sealed tube 21 having a diameter of 50 mm, which is the same as in the first embodiment, but this quartz ampoule has a constricted part 21a at the top. An example of 10g of Zn5e single crystal ■4 used as an adsorbent is placed inside, and Zn5e single crystal, W
+ 150g of 52, 10111g of Zn of transporter 13
After installing each interior and applying vacuum sealing in the same manner as in the first embodiment,
Placed in an electric furnace with temperature distribution shown in FIG.
The same heat treatment as in the example is applied.

C in Zn5e single crystal 52 treated as mentioned above
Impurities such as u, AQ, Cr, etc. are transported to the low temperature part of the sealed tube 11 by the transporter 13 (first embodiment), or to the Zn5e single crystal 1 for adsorption, which is housed in the top of the sealed tube 21 and is located in the low temperature part.
4 (Second Example), and is deposited or adsorbed.

The impurity concentration in the Zn5e single crystal to be treated 52 generated by the above treatment is determined by ICP (Injected Couple
The results are shown in Table 4 below.

As shown in Table 4, heat treatment significantly improved the purity of raw materials, and was particularly effective in extracting metals such as Cr and Cu. Zn5e single crystal 1 in adsorption in
The results of comparing the amount of impurities before and after the treatment in No. 4 are shown in Table 5 below.

It was also confirmed that more than 70% of the twins in the Zn5a single crystal extracted after two weeks of heat treatment had disappeared, and that the Zn5a single crystal was of high quality. Furthermore, it was confirmed that the obtained single crystal had a white color, which indicated that the band gap was large.

Next, the sealed tube used in the third example and its internal arrangement are
A cross-sectional view is shown in Figure 4. As shown in FIG. 14, a Zn5a single crystal 52, which is a material obtained by the Bridgman method, is placed in a sealed tube 11 made of a heat-resistant material, such as quartz, to form an atmosphere inside the sealed tube and to absorb the contents of the raw material. Impurity transporter 1
At least one S selected from Zn, a chalcogen element, especially Se, and a halogen element, especially iodine, and Zn5, which adsorbs impurities transported by the impurity transporter.
e single crystal 14 is enclosed, and 10-')
Evacuate the tube to a level of r) and melt-seal the top of this sealed tube. The sealed tube 11 to be taken up is placed with the bottom part where the Zn5e single crystal 52 and the transporter 13 are placed in the high temperature part of the heating furnace, and the top part in the low temperature part of the heating furnace, and is kept in this state for about two weeks, for example. A heat treatment is applied.

This heat treatment was carried out in a heating furnace with the temperature gradient shown in FIG.
Apply at °C. As a result, the raw material crystal Zn5e52
Impurities such as Cu, i, and Cr are transported to the low temperature part by the transporter 13 and deposited therein.

In the above heat treatment, a quartz ampoule with a diameter of 501 m and a length of 150 mm is used as the sealed tube 11, and Zn5e is added to the bottom of the quartz ampoule.
After placing 15 g of the single crystal 52, 10 g of Zn in the transporter 13, excess S, and 10 g of the Zn5e single crystal 14 used as the top adsorbent, and performing the vacuum sealing described above, It was placed in an electric furnace with the temperature distribution shown in Figure 2 and heat treated.

ZnSSe single crystal 6 extracted after two weeks of heat treatment
It was confirmed that more than 70% of the twins in the crystal No. 2 had disappeared, and the quality was high.

The atmosphere for the heat treatment during sampling is 10 atmospheres or more. Further, the heat treatment temperature is selected and set within the range of 700°C to 1250°C. Furthermore, although the case where the temperature difference between the high temperature part and the low temperature part is 10°C has been exemplified, the present invention is not limited to this, and is effective as long as it is within 100°C.

Next, in the fourth embodiment shown in FIG. 15, a quartz ampoule with a sealed tube 21 having the same diameter of 50 ny++ as in the third embodiment is used.
1a is provided, and Zn5 is used as an adsorbent here.
10g of e single crystal 14 is placed inside, and Zn5e is placed on the bottom.
150 g of the single crystal body 52, Zn of the transporter 13, and an excess amount of S of 10. After being placed inside and vacuum-sealed in the same manner as in the first embodiment, they are placed in an electric furnace having the temperature distribution shown in FIG. 2 and subjected to the same heat treatment as in the first embodiment.

C in Zn5e single crystal 52 treated as mentioned above
Impurities such as u, AQ, Cr, etc. are transported to the low temperature part of the sealed tube 11 by the transporter 13 (first embodiment), or to the Zn5e single crystal 1 for adsorption, which is housed in the top of the sealed tube 21 and is located in the low temperature part.
4 (Second Example), and is deposited or adsorbed.

The concentration of S in the single crystal obtained by extraction is:

As shown in FIG. 16, this single crystal was found to be extremely uniform in the longitudinal direction.

Zn5Sejl-1? i
The impurity concentration in the product 62 is measured by ICP (Injected
The results are shown in Table 6 below.

Next, as a fifth example, in order to set the atmosphere to an example of Se, 100 mg of Se was sealed together with zinc chalcogenide to be treated in a second sealed tube, and the high temperature part was heated to 950°C.

The low temperature section was maintained at 900°C and heating was continued for approximately 0 days.

After cooling and extraction processing, the growth state of the polycrystalline body is compared with that of a polycrystalline body not using Se using micrographs, as shown in FIGS. 17 and 18. That is, in FIG. 17, which was treated by the method of the present invention, a good single crystal state was observed, indicating that the progress toward single crystallization was significantly accelerated. On the other hand, twin crystals are clearly recognized in FIG.

Note that almost similar results were obtained when the atmosphere was Zn.

Next, thirteenth to sixteenth embodiments of the invention will be described with reference to FIGS. 19 to 24.

FIG. 19 shows a sectional view of the sealed tube used in the embodiment of the thirteenth invention and its internal arrangement. As shown in FIG. 19, polycrystalline Zn5e, which is an example of a raw material 12 previously produced by the CVD method, and a large amount of Zn13 forming an atmosphere inside the sealed tube are sealed in a sealed tube 11 made of a heat-resistant material such as quartz. 10
- Evacuate the tube to a temperature of approximately 1.5 Torr, and melt-seal one end.The sealed tube 11 taken up is placed in a soaking section of a heating furnace, and heat treatment is performed in this state for about 20 hours, for example. This heat treatment is performed at a treatment temperature of 1000° C. in a heating furnace with a temperature distribution shown in FIG.

-"The second heat treatment is performed on the sealed tube 11 with a diameter of 20 on+ as an example.
, a quartz ampoule with a length of 200 m was used, and one end of the quartz ampoule was
After 20 g of n5e12 and 30 g of Zn of extract 13 were placed inside and vacuum-sealed as described above, they were placed in an electric furnace with a temperature distribution shown in FIG. 20 and heat-treated.

Subsequently, as shown in FIG. 21, the raw material 22 that has undergone the pick-up treatment and Zn 23 and iodine 24 that form the atmosphere inside the sealed tube are sealed in a sealed tube 21 made of quartz.
) - Evacuate to about Torr and seal the top of the sealed tube. The bottom of the sealed tube 21 where the raw material 22 and transport bodies 23 and 24 are placed is placed in the high temperature part of the heating furnace.
The top portions are each placed in the low temperature section of a heating furnace, and heat treatment is performed in this state for about two weeks, for example. This heat treatment is carried out in a heating furnace having the temperature gradient shown in FIG. 2, with a high temperature of 850° C. and a low temperature of 840° C., for example. The above heat treatment is applied to the sealed tube 21, for example, with a diameter of 20 on and a length of 5 mm.
Using a 0ra quartz ampule, 10 g of raw material Zn5e22 treated as described above, 100 μ of Zn23 as an impurity transporter, and 50 μ of iodine 24 were placed in the bottom of the ampoule, and the vacuum sealing was performed as described above. It was placed in an electric furnace with the temperature distribution shown in FIG. 2 and heat treated.

Furthermore, using the same sealed tube as shown in FIG.
orr) and melt-seal the top of this sealed tube.

Thereafter, the finished sealed tube 31 is heat treated under the same treatment conditions as the finished sealed tube 21. In addition, Zn of the raw material in the example
10 g of 5e, 50 μ of Se, and 50 μ of iodine were placed at the bottom.

Cu in polycrystalline Zn5e32 processed as above
.

Impurities such as AQ and Cr are extracted from the extract 13. Transporter 23.2
4, 33, and 34, and are adsorbed or deposited in the low-temperature part.

In this way, the impurity concentration of the raw material and each impurity after the heat treatment is determined by ICP (Injected Couple Coupling Process).
The results shown in Table 7 below were obtained.

As shown in Table 7 below, it was revealed that the heat treatment significantly improved the purity of the raw materials, and was particularly effective in extracting heavy metals such as Cu and Cr.

Next, a second embodiment will be described. FIG. 22 shows a sectional view of the sealed tube used and its internal arrangement. As shown in FIG. 22, at the bottom of the sealed tube 51 made of quartz, for example,
Polycrystalline Zn5e, which is an example of the purified raw material 52, and a chemical transporter 53 such as iodine are also placed in the constriction 51a at the top of the sealed tube 51, and a seed crystal 54 of single-crystalline Zn5e is placed, respectively.

Thereafter, the sealed tube 51 was subjected to crystal growth in a heating furnace having the temperature distribution shown in FIG. 2, and a Zn5e single crystal grown body 55 shown in the figure was obtained. In addition, polycrystalline Zn5 as the raw material in the example
After placing 10 g of iodine and 50 g of iodine at the bottom, and placing the seed M54 single crystal Zn5e at the constriction 51a at the top, the inside of the sealed tube was evacuated to about 10-' Torr to stop the crystal growth. conduct.

Next, a third embodiment will be described. In the first embodiment, a quartz ampoule was used, and a high-purity single crystal Z was used as described above.
n5e62 and 363, which forms the atmosphere inside the sealed tube and acts as a diffusion material, are sealed to form a 10-6 Torr (Torr)
) and melt-seal the top of this sealed tube. The finished sealed tube 61 is placed with the Zn5e crystal 62 and the diffusion material 63 in a soaking section of a heating furnace, and is heat-treated in this state for about one week, for example. This heat treatment is performed at a treatment temperature of 1000° C. in a heating furnace having the temperature distribution shown in FIG. 20. 1
After the heat treatment for a week, the ZnSSe crystals extracted had a white color, which confirmed that the band gap had increased. Furthermore, as shown in FIG. 23, it was clear that S was distributed uniformly within the crystal.

Next, a fourth example shown in FIG. 24 shows a blue light emitting element. In the figure, 71 is an n-type Zn5e substrate crystal obtained by the iodine transport method using the raw material obtained in the present invention, and on this is a MOCVD method using dimethylzinc (DMZ) and dimethylselenium (DMSe) as raw materials. The n-type Zn5e crystal layer 72. P-type Zn5e crystalline layers 73 were sequentially laminated to form a pn junction type light emitting device. On this occasion,
The main n-type impurity of the n-type Zn5e crystal layer 72 is CQ, and the main p-type impurity of the p-type Zn5e crystal layer 73 is Li. Zn5ev: An InGa electrode 74 is formed as an n-type electrode on the back surface of the plate 71, and a p-type Zn5e layer 7
On the surface of No. 3, an AuZn electrode 75 is formed as a p-type electrode.

The light-emitting device thus obtained exhibited good blue light emission and exhibited excellent light-emitting characteristics.

According to the present invention, it is possible to extremely easily and rapidly purify the ■-■ group compound semiconductor material, which has been difficult to achieve high purity in the past, and gettering of various impurities is possible by repeatedly applying this heat treatment. Further, according to the present invention, large-sized and high-quality Zn
It has also become possible to obtain SSe crystals.

Furthermore, by using this high-quality ZnSSe crystal as a raw material, creating a single crystal from it, and using this as a substrate crystal,
A semiconductor light-emitting device exhibiting good blue light-emitting characteristics can be obtained, and uniformity in quantity production and light-emitting characteristics can be achieved.

In addition, although Zn5e was explained in the above example, similar effects can be obtained with ZuS, ZnTe, CdSe, CdT.
Needless to say, the present invention can be applied to other ■-VI group compound semiconductor materials such as e.g. Further, it goes without saying that all the single crystal substrates manufactured by the method for manufacturing a II-VI group compound semiconductor single crystal described above can be applied to the substrate applied to this light emitting element. Furthermore, the growth method for the n-VI group compound semiconductor layer is not limited to the MOCVD method.
It is possible to use other vapor phase growth, MBE methods, or liquid phase growth methods.

In addition, the present invention can be implemented with various modifications without departing from the spirit thereof.

〔Effect of the invention〕

According to the present invention, n −
Purification of Group VI compound semiconductor materials can be achieved extremely easily, and by repeatedly performing this heat treatment, gettering of various impurities is possible. The polycrystalline compound semiconductor raw material purified in this way can be used for vapor phase growth, solid phase growth,
Alternatively, it is possible to use it for liquid phase epitaxial use to form highly pure crystalline materials, and to improve the purity of these compound semiconductor single crystals.

A semiconductor layer of a light emitting layer is formed on the single crystal substrate thus obtained by MOCVD method or the like, and the light emitting efficiency is determined.

A blue light emitting element with excellent light emitting characteristics can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing a sealed tube used in the embodiments of the first to third inventions and the arrangement of raw materials etc. placed inside the tube, and FIG. 2 is a sectional view of the sealed tube used in the embodiments of the present invention. Diagram showing heat treatment conditions; FIG. 3 is a sectional view showing the state of sealed tubes used in the fourth and fifth embodiments of the invention after heat treatment;
The figure is a sectional view showing the arrangement of the sealed tube and the single crystal etc. installed inside the tube used in the embodiment of the sixth and seventh inventions, and FIG. FIG. 6 is a cross-sectional view showing the state of the sealed tube after heat treatment, and FIG. Figure 7 is a diagram comparing the absorption, and compares the room temperature photoluminescence spectra of single crystals obtained by crystal growth of the one doped with iodine and Zn according to the present invention and the one doped with only iodine. A diagram, FIG. 8 is a diagram showing the correlation between Zn doping amount and crystal growth rate according to the present invention, FIG. 9(a). (b) is a single crystal Zn5 produced by solid phase diffusion according to the eighth invention.
10 and 11 are sectional views each showing a sealed tube of another embodiment according to the eighth invention, and FIGS. 12 and 13 are sectional views showing the manufacturing process of e. 9th
A sectional view showing the arrangement of the sealed tube and the Zn5e single crystal etc. contained therein used in the embodiments of the 11th to 11th inventions, 1st
4 and 15 are cross-sectional views showing the arrangement of the sealed tube and the ZnSSe single crystal etc. contained therein used in the embodiments of the ninth to eleventh inventions, and FIG. 16 is a cross-sectional view showing the arrangement of the ZnSSe single crystal, etc. FIG. 17 is a diagram showing the concentration of S in the single crystal body obtained by the embodiment of the invention, FIG. 19 is a micrograph showing the crystal structure of a crystal containing twins; FIG. 19 is a sectional view showing the arrangement of the sealed tube and the raw materials contained therein used in the embodiments of the thirteenth to sixteenth inventions; Fig. 20 is a diagram showing the temperature distribution of the heating furnace used in the embodiments of the 13th to 16th inventions, and Figs. 21 and 22 are the sealed tubes used in the embodiments of the 13th to 16th inventions. A cross-sectional view showing the state after heat treatment,
FIG. 23 is a diagram showing the concentration of S in the ZnSSe single crystal obtained by the embodiments of the 13th to 16th inventions, and FIG. 24 is a diagram showing the pn junction formed by the embodiments of the 13th to 16th inventions. FIG. 2 is a cross-sectional view of a type light emitting device. 11, 21.31.51...Sealed tube 12, 32.52...Raw material 13, 33.53...Chemical transporter 14, 54...Seed crystal 15...Zn melt 17... - Supporting members 23, 24 - Chemical transporter 71 - N-type Zn5e substrate 72 - N-type Zn5e seed crystal layer 73 - P-type Zn5e crystal layer 74 - InGa electrode 75 - AuZn electrode agent Patent attorney Dai Hu Dianfu Figure 1 Figure 2
3 Figure 4 Figure'll
a: <σ hole @ z÷=4 100 crystals 1 piece @ 5
Figure 6 Figure 7 Figure 8 Figure 3z: Ya ≧ tongue crystal Z,, Ls go 2
: j Ea Seven Adventures Sε No. 9 Figure z2 : Tatake Tongue Crystal : ZrLse 1g : grb
Qk No. 10 l71 31 ; Multi-T product La5a Fig. 11 Fig. 12 Fig. 13 , 2 one・: iF−ξ? ＊嬌jI Main Act Act 21 Figure 22 Figure 24

Claims (16)

[Claims] (1) When purifying a compound semiconductor using a sealed tube, a II-VI compound semiconductor is placed in a high-temperature part of a sealed tube with a temperature difference, and impurities in this compound semiconductor are transported to a low-temperature part of the sealed tube. A method for purifying a II-VI group compound semiconductor, characterized by improving the purity of the compound semiconductor. (2) The method for purifying a II-VI group compound semiconductor according to claim 1, wherein the inside of the sealed tube is carried out in a mixed atmosphere of either a group II element or a group VI element, or one of the above-mentioned both group elements and a halogen element. (3) When purifying a compound semiconductor using a sealed tube, a II-VI compound semiconductor is placed in the high-temperature part of the sealed tube with a temperature difference, and an impurity adsorbent is placed in the low-temperature part to seal impurities in the compound semiconductor. 1. A method for purifying a II-VI group compound semiconductor single crystal, the method comprising transporting it to a low-temperature section in a tube to improve its purity. (4) When manufacturing a compound semiconductor single crystal using a sealed tube, a group II-VI compound semiconductor is placed in the high-temperature part of the sealed tube with a temperature difference, and an impurity adsorbent is placed in the low-temperature part. 1. A method for producing a group II-VI compound semiconductor single crystal, which comprises transporting impurities to a low-temperature part within a sealed tube to improve purity and form a single crystal. (5) The production of a II-VI group compound semiconductor single crystal according to claim 4, wherein the production is carried out in a sealed tube in a mixed atmosphere of either a group II element or a group VI element, or one of the above-mentioned both group elements and a halogen element. Method. (6) In manufacturing compound semiconductors using sealed tubes, a II-VI group compound semiconductor is placed in the high-temperature part of the sealed tube with a temperature difference, and a single crystal of the same type is placed in the low-temperature part, and single crystal growth is performed. A method for producing a II-VI group compound semiconductor single crystal, characterized in that: (7) In manufacturing a compound semiconductor using a sealed tube, a polycrystalline material of a II-VI group compound semiconductor is placed in the high-temperature part of the sealed tube with a temperature difference, and a single crystal of the same type is placed in the low-temperature part. It is characterized by growing the same type of single crystal in a sealed tube with a mixed atmosphere of group II or group VI elements and halogen elements.
A method for producing a II-VI group compound semiconductor single crystal. (8) When manufacturing a compound semiconductor single crystal using a sealed tube, a polycontainer of the II-VI compound semiconductor is added to the melt of the group II elements constituting the group II-VI compound semiconductor in the high-temperature part of the sealed tube with a temperature difference. I, characterized in that the polycrystalline body is made into a single crystal by solid phase growth by arranging a crystalline body and raising the temperature to a predetermined temperature.
A method for manufacturing a group I-VI compound semiconductor single crystal. (9) A method for producing a group II-VI compound semiconductor single crystal, in which a group II-VI compound semiconductor material is melted at a predetermined temperature from one end, and the melted portion is sequentially transferred to the other end of the material to achieve single crystallization, solidifying and forming a polycrystal in a first sealed tube; and transferring the solidified crystal to a second sealed tube having a larger diameter than the first sealed tube so as to reduce the contact area with the inner wall. A method for producing a II-VI group compound semiconductor single crystal, comprising the steps of re-encapsulating the compound semiconductor crystal, and performing a heat treatment at a temperature lower than the melting temperature of the II-VI group compound semiconductor crystal to form a single crystal. (10) The method for producing a II-VI group compound semiconductor single crystal according to claim 9, wherein the heat treatment performed in the second sealed tube is performed with an impurity adsorbing crystal placed in the low temperature part. (11) Group II elements, V
10. The method for producing a II-VI group compound semiconductor single crystal according to claim 9, wherein the method is performed by enclosing an excess of a group I element or a halogen element. (12) In manufacturing a compound semiconductor using a sealed tube, a single crystal of a II-VI compound semiconductor is placed in the high temperature part of the sealed tube with a temperature difference, and a single crystal of the same type is placed in the low temperature part. 1. A method for producing a group II-VI compound semiconductor single crystal, which comprises growing a single crystal in a sealed tube in a mixed atmosphere of a group II or group VI element and a halogen element. (13) Create a temperature difference in the sealed tube, and place II-V in the high temperature part inside the sealed tube.
A polycrystal of a group I compound semiconductor is placed in a melt of a group II element constituting the polycrystal, a group II-VI compound semiconductor single crystal substrate is formed by solid phase growth, and a group II-VI compound semiconductor single crystal substrate is placed on this single crystal substrate. A method for manufacturing a semiconductor light emitting device in which epitaxial layers of the same type are stacked and this epitaxial layer is used as a light emitting layer. (14) A crystal of a group II-VI compound semiconductor is placed in the high-temperature part of a sealed tube with a temperature difference, and a single crystal of the same type is placed in the low-temperature part, and the inside of this sealed tube is filled with a group II or group VI compound semiconductor. Single crystal growth is performed in a mixed atmosphere of halogen elements to form a II-VI group compound semiconductor single crystal substrate, and an epitaxial layer of the same type as this is laminated on this single crystal substrate, and this epitaxial layer is used as a light emitting layer. A method for manufacturing a semiconductor light emitting device. (15) The method for manufacturing a semiconductor light emitting device according to claim 13 or 14, wherein the light emitting layer is formed by metal organic vapor phase epitaxy. (16) The method for manufacturing a semiconductor light emitting device according to claim 13 or 14, wherein the light emitting layer is formed by liquid phase growth using at least one of its constituent elements.