WO2008029827A1

WO2008029827A1 - PROCESS FOR PRODUCING AlN CRYSTAL

Info

Publication number: WO2008029827A1
Application number: PCT/JP2007/067265
Authority: WO
Inventors: Kanji Otsuka; Yoshihiro Seimiya; Kenji Takagi; Kaoru Sugita
Original assignee: Tama-Tlo Ltd.
Priority date: 2006-09-07
Filing date: 2007-09-05
Publication date: 2008-03-13
Also published as: JPWO2008029827A1; JP5229735B2

Abstract

A novel process for producing an AlN crystal. The process for AlN crystal production comprises bringing a seed crystal (4) into contact with molten aluminum (2) located in a nitrogenous atmosphere, supplying to the interface between the seed crystal (4) and the molten aluminum (2) an element having a smaller free energy concerning nitride formation than aluminum (e.g., boron, calcium, or silicon), and reacting nitrogen dissolved in the molten aluminum (2) with the molten aluminum (2) using that element as a catalyst to grow an AlN crystal on the seed crystal (4). The nitrogenous atmosphere is preferably regulated so as to have a pressure of 4 atm or higher. The temperature of the interface between the molten aluminum (2) and the seed crystal (4) is preferably regulated to 800°C or higher. The element serving as a catalyst may be supplied to the interface between the seed crystal (4) and the molten aluminum (2) by incorporating the gas of a compound containing the element serving as a catalyst into the nitrogenous atmosphere and dissolving this gas in the molten aluminum (2).

Description

Specification

A1N crystal manufacturing method

Technical field

[0001] The present invention relates to a novel method for producing an A1N crystal.

Background art

[0002] Compound semiconductor devices are used for semiconductor devices and high-luminance light-emitting devices. The characteristics required for a substrate of a single device or a high-intensity light emitting device include that the compound semiconductor and the lattice constant are matched, that the band gap is large, and that the heat dissipation is good. Conventionally, a compound semiconductor device has been formed by forming a buffer layer with a special structure on a Si single crystal substrate or a sapphire substrate, and forming a compound semiconductor layer on the buffer layer.

Disclosure of the invention

Problems to be solved by the invention

[0003] As described above, in the conventional method, it is necessary to form a buffer layer with a devised structure between the substrate and the semiconductor layer. For this reason, the manufacturing cost is high.

On the other hand, A1N has a large band gap in the ultraviolet region, high thermal conductivity, and good lattice constant matching with AlGaN, etc., so when A1N is used as a substrate for a compound semiconductor device, a buffer layer is used. There is no need to form. However, it was impossible to grow A1N crystals with good crystallinity to a sufficient size.

[0004] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a novel A1N crystal manufacturing method capable of growing an A1N crystal having good crystallinity. Me · ο.

Means for solving the problem

[0005] When the present inventors insert A1 and any element whose free energy of formation of nitride is smaller than A1 into the same container and heat it in a nitrogen atmosphere to melt A1, the element is touched. We have found that A1 reacts with nitrogen in the atmosphere as a medium to produce A1N. For example, when ΒΝ is used, it is considered that A1B, which is a compound of A1 and Β, is generated first. And the frog A1N is generated by combining with B contained in A1B and then passing it to A1.

12

[0006] The present invention has been made based on this finding. That is, in the method for producing an A1N crystal according to the present invention, a seed crystal is brought into contact with the molten A1 located in a nitrogen atmosphere, and the free energy of formation of nitride is A at the interface between the seed crystal and the molten A1. Supply small elements,

A1N crystal is grown on the seed crystal by reacting nitrogen dissolved in the molten A1 with the element as a catalyst and the molten A1.

[0007] The element is at least one selected from the group consisting of, for example, boron, calcium, silicon, iron, molybdenum, chromium, vanadium, magnesium, manganese, indium, gallium, tantalum, hafnium, and thorium force. . The nitrogen atmosphere is preferably 4 atm or more. Further, the temperature at the interface between the molten A1 and the seed crystal is preferably set to 800 ° C or higher. The element may be supplied to the interface between the seed crystal and the molten A1 by mixing a gas of a compound containing the element in the nitrogen atmosphere and dissolving the gas in the molten A1.

The invention's effect

[0008] According to the present invention, an A1N crystal can be produced by a novel method.

Brief Description of Drawings

FIG. 1 is a schematic vertical sectional view for explaining the configuration of an A1N manufacturing apparatus used in the A1N manufacturing method according to the first embodiment.

FIG. 2 is a schematic longitudinal sectional view for explaining the configuration of an A1N manufacturing apparatus used in the A1N manufacturing method according to the second embodiment.

Explanation of symbols

[0010] 2… Melting A1

4 ...

10 · · · Container

20 ... Heater

30 · · · Seed crystal holding part

32 ··· 1 Supply Department 34 ··· Catalyst element supply section

50 ... Chamber one

52 ··· Nitrogen gas supply section

54 ... Pump

56 · · · Gas supply section containing catalyst element

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic longitudinal sectional view for explaining the configuration of an A1N manufacturing apparatus used in the A1N manufacturing method according to the first embodiment of the present invention. This A1N manufacturing apparatus includes a container 10 for holding molten A12, a heater 20 for heating the molten A1 in the container 10, a seed crystal holding unit 30 for holding the seed crystal 4, and an A1 supply unit 32 for supplying A16 to the molten A12. And a catalytic element supply unit 34 for supplying a substance (hereinafter referred to as a catalyst element-containing material) containing an element functioning as a catalyst (hereinafter referred to as a catalytic element) to the molten A1. Each of these components is disposed within the chamber 50. The inside of the chamber 50 can be made into a nitrogen atmosphere pressurized by the nitrogen gas supply unit 52. The inside of the chamber 50 can be evacuated by a pump 54.

[0012] The catalytic element is an element whose free energy of formation of nitride is smaller than A1, for example, boron, calcium, silicon, iron, molybdenum, chromium, vanadium, magnesium, manganese, indium, gallium, tantalum, hafnium. And at least one selected from the group consisting of thorium. The catalytic element-containing material may be a single element, nitride (eg, BN, Si N, or Ca N), or carbide (eg, B C).

3 4 3 2 4

good.

[0013] The seed crystal has, for example, a force S, which is an A1N crystal, and the same hexagonal crystal structure as the A1N, and the lattice constant based on the lattice constant of A1N is 65% or more and 135% or less or It may be a crystal (for example, Si N, BN, or GaN) made of a material that is 150% or more and 250% or less and whose free energy of formation is closer to that of A1N. The lattice constant of the seed crystal is A1N

3 4

When the lattice constant is 65% or more and 135% or less, the seed crystal and the A1N crystal have a one-to-one lattice match, and when the seed crystal has a lattice constant of 150% or more and 250% or less of the A1N lattice constant, The crystal and A1N crystal have a one-to-two lattice match. Next, a method for manufacturing A1N using the A1N manufacturing apparatus of FIG. 1 will be described. First, insert the A1 piece into the container 10. Next, after the inside of the chamber 50 is evacuated by the pump 54, the nitrogen gas is supplied into the chamber 50 by the nitrogen gas supply unit 52. As a result, the inside of the chamber 150 becomes a nitrogen atmosphere. The pressure in the nitrogen atmosphere is preferably 4 atm or more and 30 atm or less, but may be normal pressure. Next, a predetermined amount of catalyst element-containing material is supplied into the container 10 and the A1 piece is melted using the heater 20. As a result, molten A12 in which the catalytic element is dissolved is generated in the container 10. The temperature of the melted A12 at this time is preferably 800 ° C or higher and 1300 ° C or lower.

[0015] Next! /, The bottom surface of the seed crystal 4 is immersed in the molten A12 while rotating the seed crystal 4 held by the seed crystal holding unit 30. A catalytic element is located at the interface between seed crystal 4 and molten A12. In this state, the catalytic element reacts with the nitrogen dissolved in the molten A12 and nitrides. As described above, the catalytic element has a lower free energy of formation of nitride than aluminum. For this reason, the nitrogen combined with the catalytic element is transferred to the aluminum, and the aluminum is nitrided. In this way, the nitriding reaction of aluminum using the catalytic element as a catalyst proceeds, and thereby an A1N crystal grows on the seed crystal 4. While the A1N crystal grows, the concentration of the catalyst element contained in the molten A12 is controlled to an optimum value by adding A16 and the catalyst element-containing material as appropriate by the A1 supply unit 32 and the catalyst element supply unit 34. As a result, the growth of the A1 N crystal in the seed crystal 4 is continued, and an A1N crystal rod is formed. Also, by adjusting the conditions, an A1N single crystal rod can be produced.

[0016] It should be noted that the temperature of the molten A1 and the pressure of the nitrogen atmosphere are set to the conditions immediately before the A1N formation reaction occurs, and heating means for heating the temperature of the interface between the seed crystal 4 and the molten A12 (not shown) ) To increase only the interface temperature.

[0017] As described above, according to the present embodiment, it is possible to generate A1N crystal rods by the pulling method (CZ method). A1N single crystal rods can be produced by adjusting the conditions.

Yes

FIG. 2 is a schematic longitudinal sectional view for explaining the configuration of an A1N manufacturing apparatus used in the A1N manufacturing method according to the second embodiment of the present invention. The A1N manufacturing apparatus shown in the figure has the first element except that the catalyst element-containing gas supply unit 56 is provided instead of the catalyst element supply unit 34. The configuration is the same as that of the AIN manufacturing apparatus according to the embodiment. Hereinafter, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

[0019] The catalyst element-containing gas supply unit 56 mixes a gas of a compound containing a catalyst element (for example, B H or SiH) in a nitrogen atmosphere. By making these gases melt and infuse into the molten A1

2 6 4

Then, melt the catalyst element into the molten A1.

[0020] The manufacturing method of A1N according to the present embodiment, except that the catalytic element-containing gas supply unit 56 is used instead of the catalytic element supply unit 34, and the catalytic element is melted and injected into the molten A1. This is the same as the manufacturing method of A1N according to the first embodiment.

According to this embodiment, the same effect as that of the first embodiment can be obtained.

It should be noted that the present invention is not limited to the above-described embodiment, and can be implemented with various modifications without departing from the spirit of the present invention.

Claims

The scope of the claims

[1] Place the seed crystal in contact with the molten A1 located in a nitrogen atmosphere,

An element having a small free energy of formation of nitride is supplied to the interface between the seed crystal and the molten A1,

A method for producing an A1N crystal, wherein an A1N crystal is grown on the seed crystal by reacting the molten A1 with nitrogen dissolved in the molten A1 using the element as a catalyst.

[2] The element according to claim 1, wherein the element is at least one selected from the group consisting of boron, calcium, silicon, iron, molybdenum, chromium, vanadium, magnesium, manganese, indium, gallium, tantalum, hafnium, and thorium. The manufacturing method of A1N crystal of description.

[3] The method for producing an A1N crystal according to claim 1 or 2, wherein the nitrogen atmosphere is 4 atm or more.

Yes

[4] The method for producing an A1N crystal according to any one of claims 1 to 3, wherein a temperature at an interface between the molten A1 and the seed crystal is set to 800 ° C or higher.

[5] The element is supplied to an interface between the seed crystal and the molten A1 by mixing a gas of the compound containing the element in the nitrogen atmosphere and dissolving the gas in the molten A1. The manufacturing method of the A1N crystal as described in any one of -4.