JPH05217911A - Vapor growing apparatus - Google Patents

Abstract

PURPOSE:To reduce the consumption of mercury and to decrease the cost of vapor growth by providing a trap at a downstream side of a substrate, solidifying mercury which does not contribute to a crystal growth to recover it, and then circulating it to a mercury reservoir. CONSTITUTION:A crystal is grown by an MOCVD method using DMCd, DIPTe as material gases. Residual material which is not used for the growth is called to a trap 6. Since coolant flowing to a drain port 6b in fed from a pouring port 6a via blades 6a in the trap 6, the trap 6 is cooled to 200 deg.C. Accordingly, mercury having a boiling point higher than those of the DMCd, DIPTe is solidified to the trap 6. Mercury solidified to a tray 7 cooled to the ambient temperature or lower by a cooler 8 is dropped, and recovered to the tray 7. It is circulated from the tray 7 to a mercury reservoir 3 through a circulating pipe 5. Thus, consumption amount of the mercury can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention can efficiently supply mercury without waste and reduce mercury consumption when growing a compound semiconductor crystal containing mercury, which is a fluid at room temperature, by a vapor phase method. The present invention relates to a vapor phase growth apparatus that is made possible.

[0002]

2. Description of the Related Art FIG. 7 shows, for example, a document (Jounal of Crysta
MOCVD (Metal Organic Chemical Vapor) which has been widely used in the past as shown in Growth 65 (1983) 479-484).
It is a schematic structure explanatory drawing of a Deposition) apparatus. Conventional M
In the crystal growth of a compound containing mercury by a vapor phase growth method such as the OCVD method, the mercury 9 in the mercury reservoir 3 is heated by the mercury heating unit 4 to become mercury vapor, and the carrier introduced from the gas supply port 1 is introduced. The gas is carried to the substrate 10 heated by the substrate heating unit 11.

Thus, part of the supplied mercury was used for crystal growth, and the mercury that was not used for growth was exhausted from the gas exhaust port 2 and was not reused.

[0004]

As described above, the conventional M
In the OCVD apparatus, since the mercury discharged from the exhaust port from the reactor is not reused, there is a problem that the consumption amount of mercury is large and the cost is high.

The present invention has been made to solve the above-mentioned conventional problems, and an object thereof is to obtain a vapor phase growth apparatus that consumes a small amount of mercury during crystal growth.

[0006]

A vapor phase growth apparatus according to the present invention is a trap arranged downstream of a substrate on which a compound semiconductor crystal is mounted in a reactor, for trapping mercury on the exhaust side in the reactor. And a reflux means for refluxing the mercury condensed in the trap to the mercury reservoir.

[0007]

In the trap according to the present invention, mercury that has not participated in the growth of semiconductor crystals in the reactor is condensed on the downstream side of the substrate, and the condensed mercury is returned to the mercury reservoir by the reflux means to recover the mercury. , Recycle the recovered mercury.

[0008]

Embodiments of the vapor phase growth apparatus of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view showing the configuration of the embodiment, and FIG. 2 is a side view thereof. 1 and 2, the same parts as those of the conventional example shown in FIG. 7 are designated by the same reference numerals.

In the first embodiment shown in FIGS. 1 and 2, the infrared detector material Cd _x Hg _1-x Te is applied to a CdTe substrate,
The case of growing by a horizontal reactor MOCVD method having an internal mercury reservoir will be described as an example.

Crystal growth is performed by the MOCVD method using DMCd (dimethyl cadmium) and DIPTe (diisopropyl tellurium) as material gases. CdTe substrate 10
Is placed on the substrate heating unit 11 as a heating means. The substrate heating unit 11 is provided in the reactor, that is, M
It is installed in the OCVD equipment. The substrate 10 is a substrate made of a compound semiconductor crystal composed of plural kinds of elements including mercury.

A mercury reservoir 3 is housed in the reactor. The mercury reservoir 3 is filled with mercury 9. The mercury reservoir 3 is arranged on the upstream side of the substrate heating unit 11. In order to heat this mercury 9, a mercury heating unit 4 is provided on the outer peripheral surface of the reactor.

A trap 6 is disposed in the reactor on the downstream side of the substrate 10 so that mercury that does not contribute to crystal growth is condensed and the condensed mercury is dropped into the tray 7. A reflux pipe 5 is connected as a reflux means between the tray 7 and the mercury reservoir 3.
Mercury is caused to flow back into the mercury reservoir 3 through the reflux pipe 5. In addition, 1 is a gas supply port provided in the reactor, and 2 is a gas exhaust port.

As is apparent from the front view shown in FIG. 4 and the perspective view shown in FIG. 5, the trap 6 has a water injection port 6a and a drainage port 6b and has vanes 6 for receiving the flowing gas.
The blade 6c is cooled by the cooling water flowing from the water inlet 6a to the water outlet 6b.

Next, the operation will be described. Substrate 10 is M
The substrate is placed on the substrate heating unit 11 in the OCVD apparatus, the mercury reservoir 3 corresponding to the mercury heating unit 4 is filled with mercury 9, and the substrate heating unit 11 is heated in a hydrogen flow to reach a predetermined temperature. After that, the state is maintained and the raw materials DMCd and DIP are used.
Te and mercury are supplied from the gas supply port 1 onto the substrate 10 in the reactor using hydrogen as a carrier gas.

As for the supply of mercury, the temperature of the mercury heating section 4 is raised, and the mercury that has become vapor from the heated mercury reservoir 3 flows together with hydrogen as a carrier gas, as shown by the arrow in FIG.
Supply to the substrate 10. On this substrate 10, DMCd,
DIPTe reacts with mercury to grow Cd _x Hg _1-x Te epitaxial crystals.

The remaining raw material not used for this growth is called trap 6. The trap 6 is, as shown in FIGS.
Since the cooling water flowing in b is flowing, the trap 6 has 2
Cooled to 00 ° C. Therefore, DMCd, DI
Mercury, which has a higher boiling point than PTe, condenses in the trap 6,
The condensed mercury is dripped by the cooling unit 8 to the saucer 7 cooled to room temperature or lower, and is collected in the saucer 7. This saucer 7
Through the reflux pipe 5 to the mercury reservoir 3.

In this way, mercury is recovered by the trap 6 and the pan 7 and is refluxed and recovered by the reflux pipe 5 and the mercury reservoir 3, so that the consumption of mercury is reduced and the compound semiconductor crystal is reduced. Growth cost can be reduced. When the mercury heating temperature is 350 ° C., the trap temperature is 200 ° C., and the saucer temperature is 30 ° C., 96.6% of mercury is recovered, and the consumption amount becomes 1/30.

Next, a second embodiment of the present invention will be described. This second embodiment is applied to a vertical MOCVD apparatus, and this second embodiment also has the same effect as that of the first embodiment. Figure 6 shows this vertical MO
It is a sectional view when applied to a CVD apparatus, and shows a configuration of a second embodiment of the present invention.

In FIG. 6, the same parts as those shown in FIGS. 1 to 3 are designated by the same reference numerals to avoid redundant description.
In the case of the embodiment of FIG. 6, the mercury 9 collected in the tray 7 is heated by the heater 12 to be vaporized, and the cooling unit 1
By condensing at 3, it can be transported to the mercury reservoir 3. The other parts are the same as those in the first embodiment.

[0020]

As described above, according to the present invention, the trap is provided on the downstream side of the substrate, and the mercury which is not involved in the crystal growth is condensed and recovered, and then returned to the mercury reservoir. In addition, the mercury consumption can be reduced, and the growth cost can be reduced.

[Brief description of drawings]

FIG. 1 is a plan view showing the structure of a vapor phase growth apparatus according to a first embodiment of the present invention.

FIG. 2 is a side view showing the configuration of the first embodiment.

FIG. 3 is an explanatory diagram showing a flow of mercury vapor according to the first embodiment.

FIG. 4 is a front view of the trap according to the first embodiment.

FIG. 5 is a perspective view of the same trap.

FIG. 6 is a sectional view showing a structure of a vapor phase growth apparatus according to a second embodiment of the present invention when the present invention is applied to a vertical MOCVD apparatus.

FIG. 7 is a diagram showing the structure of a conventional MOCVD apparatus.

[Explanation of symbols]

 1 Gas Supply Port 2 Gas Exhaust Port 3 Mercury Reservoir 4 Mercury Heating Section 5 Reflux Pipe 6 Trap 7 Receptacle 8 Cooling Section 9 Mercury 10 Substrate 11 Substrate Heating Section 12 Heater 13 Cooling Section

[Procedure amendment]

[Submission date] June 15, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

Crystal growth is performed by the MOCVD method using DMCd (dimethyl cadmium) and DIPTe (diisopropyl tellurium) as material gases. CdTe substrate 10
Is placed on the substrate heating unit 11 as a heating means. The substrate heating unit 11 is provided in the reactor, that is, M
It is installed in the OCVD equipment. This substrate 10 is Cd
Te, GaAs, Si and the like .

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

[0012] downstream side of the substrate 10 is trap 6 is disposed, by condensation of mercury which do not contribute to crystal growth,
The condensed mercury is made to drip in the saucer 7. A reflux pipe 5 is connected as a reflux means between the tray 7 and the mercury reservoir 3. Mercury is caused to flow back into the mercury reservoir 3 through the reflux pipe 5. In addition, 1 is a gas supply port provided in the reactor, and 2 is a gas exhaust port.

[Procedure 3]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location H01L 31/0264

Claims (1)

[Claims] 1. A reactor for circulating a plurality of kinds of gases containing respective elements of a compound semiconductor crystal containing mercury, a heating means provided in the reactor for heating the gas, and a reactor installed in the reactor. A substrate on which the compound semiconductor crystal for reacting with the gas heated by the heating means is placed, a trap provided in the reactor for condensing mercury on the exhaust side in the reactor, and the trap condensed by the trap A vapor phase growth apparatus comprising a tray for collecting mercury and a reflux means for refluxing the mercury collected in the tray to a mercury reservoir.