CN111153700B

CN111153700B - Preparation method of nitride target material

Info

Publication number: CN111153700B
Application number: CN201911416943.1A
Authority: CN
Inventors: 王海侠; 肖伟军
Original assignee: Outaixin Optic Electric Thchnology Suzhou Co ltd
Current assignee: Suzhou Haike Semiconductor Technology Co ltd
Priority date: 2019-12-31
Filing date: 2019-12-31
Publication date: 2022-06-21
Anticipated expiration: 2039-12-31
Also published as: CN111153700A; WO2021135681A1

Abstract

The invention discloses a preparation method of a nitride target material, and belongs to the technical field of semiconductor materials. The invention adopts a solid phase method, the powder is firstly mixed by the additive, the mixture is put into a die and is made into a blank by isostatic cool pressing, and then the blank is sintered and formed into the nitride target sintered body by an atmosphere furnace at the high temperature of 600-1000 ℃, so that a plurality of target sintered bodies can be sintered, and the process production efficiency is high. And the density of the target material can be improved, and the high-density oxygen-free pure nitride target material can be obtained. The method has the characteristics of simple, convenient, economic and environment-friendly industrial production, can be used for preparing high-quality nitride nano powder and a target material in a large scale, and is applied to the field of semiconductor elements. The thin film layer produced by the nitride target material prepared by the method is compact and uniform.

Description

Preparation method of nitride target material

Technical Field

The invention relates to a preparation method of a nitride target material, belonging to the technical field of semiconductor materials.

Background

Nitrides are new semiconductor materials with great potential in electronic and optoelectronic applications, which have the advantages of high electron mobility and good electrical conductivity at room temperature. For example, the research and application of gallium nitride materials are leading edges and hot spots of current global semiconductor research, are novel semiconductor materials for developing microelectronic devices and optoelectronic devices, and are the third generation semiconductor materials following silicon and gallium arsenide. The material has the properties of wide direct band gap, strong atomic bond, high thermal conductivity, good chemical stability (hardly corroded by any acid) and the like, and strong irradiation resistance, and has wide prospects in the application aspects of photoelectrons, high-temperature high-power devices and high-frequency microwave devices.

In the prior art, a nitride film is manufactured by mainly adopting a metal target and a reaction gas as a nitrogen source or an expensive metal precursor and a nitrogen source precursor. At present, no report of pure nitride target materials exists, and the uniformity and purity of the prepared film are difficult to guarantee mainly by composite target materials, such as metal-containing Ga infiltrated gallium nitride or doped nitride target materials. The problem of metal and nitrogen decomposition under normal pressure exists in the preparation process of the pure nitride target material (for example, gallium nitride is decomposed into metal Ga and N at 700-1000 ℃, indium nitride is changed into metal indium at a certain temperature, and the like). In addition, there is a problem of oxidation in the preparation process, that is, metal Ga generated in the preparation process may become oxide, and zinc nitride may become zinc oxide at a certain temperature. The present invention provides an effective approach to nitride targets, enabling continuous production at low manufacturing costs. The method can solve the problems, and the target material has the advantages of high uniformity, no oxygen, high density, suitability for large-scale production and the like.

Disclosure of Invention

In order to solve the problems, the invention provides a preparation method of a nitride target, nitride nanoparticles with higher purity and larger specific surface area are selected as raw materials, a solid phase method is adopted, nitride powder is firstly mixed by additives, is placed into a mould and is pressed into a blank by cold isostatic pressing or hot isostatic pressing or warm isostatic pressing, and then is sintered and formed into a nitride target sintered body by an atmosphere furnace at the temperature of 600 plus materials and 1000 ℃ according to different forming conditions of nitride, a plurality of target sintered bodies can be sintered, and the process production efficiency is high. And the compactness of the target material can be improved, and the nitride target material with high density and no oxygen content can be obtained. The method has the characteristics of simple, convenient, economic and environment-friendly industrial production, can be used for preparing high-quality nitride nano powder and a target material in a large scale, and is applied to the field of semiconductor elements. The thin film layer produced by the nitride target material prepared by the method is compact and uniform.

The first purpose of the invention is to provide a preparation method of a nitride target material, which comprises the following steps:

(1) under the condition of carrier gas, grinding and screening nitride powder;

(2) adding polyvinyl alcohol into the powder in the step (1) and pre-pressing to form a blank;

(3) and (3) pre-burning and glue removing are carried out on the blank in the step (2), and then the sintering temperature is 600-1050 ℃ under the inert gas or ammonia gas or vacuum condition to obtain the nitride target material.

The sintering method may employ various sintering methods including a high-temperature solid phase method, a hot press method, and a hot isostatic pressing method. In order to obtain a nitride sintered body with high density, the hot isostatic pressing method is preferable. Wherein the atmosphere device can be a closed system or a flow-through system, preferably a flow-through system.

Further, the nitride is gallium nitride, zinc nitride or indium nitride.

Further, the nitride powder is prepared by the following method: and carrying out nitridation treatment on metal, metal oxide or metal oxyhydroxide corresponding to the nitride at the temperature of 600-1000 ℃ for 2-7 hours under the condition of ammonia gas to obtain nitride powder, wherein the purity of the oxide or the oxyhydroxide is not lower than 99.995%, and the purity of the ammonia gas is not lower than 4N. Wherein the atmosphere device can be a closed system or a flow-through system, preferably a flow-through system.

Further, the addition amount of the polyvinyl alcohol is 0.5 to 5 wt% of the nitride powder.

Further, in the step (2), the pre-pressing molding condition is that the temperature is 20-300 ℃ and the pressure is 80-100 MPa. The pre-pressing method can adopt a cold isostatic pressing method, a warm isostatic pressing method, a hot pressing method or a hot isostatic pressing method.

Further, in the step (3), the temperature of pre-burning glue discharging is 500-650 ℃.

The density of the obtained nitride sintered body is not less than 60% of the theoretical density, and the flatness of the target can be 10 μm or less. The nitride sintered body is processed into a predetermined size according to the application, and the processing method may be a surface grinding method, a rolling grinding method, a wire cutting method, a laser cutting method, a chemical mechanical polishing method, or the like.

Further, in the step (3), the inert gas is nitrogen or argon.

The second purpose of the invention is to provide a nitride target material prepared by the preparation method.

The third purpose of the invention is to provide the application of the nitride target material in semiconductor materials

The invention has the beneficial effects that: the invention adopts a solid phase method, the powder is firstly mixed by the additive, and then the mixture is put into a die to be pressed into a blank by cold isostatic pressing, and then the blank is sintered and molded into the nitride target sintered body by an atmosphere furnace at the high temperature of 600 ℃ and 1000 ℃, so that a plurality of target sintered bodies can be sintered, and the process production efficiency is high. And the density of the target material can be improved, and the high-density oxygen-free pure nitride target material can be obtained. The method has the characteristics of simple, convenient, economic and environment-friendly industrial production, can be used for preparing high-quality nitride nano powder and a target material in a large scale, and is applied to the field of semiconductor elements. The thin film layer produced by the nitride target material prepared by the method is compact and uniform.

Drawings

FIG. 1 is an X-ray diffraction pattern of gallium nitride;

FIG. 2 is a diagram of a gallium nitride target;

FIG. 3 is an X-ray diffraction diagram of indium nitride.

Detailed Description

In order to better understand the essence of the invention, the technical contents of the invention are explained in detail below by way of examples.

The purity of the nitride powder was measured by the GD-MS method, and the specific surface area was measured by the BET multipoint method.

The density of the nitride target adopts a solid density measuring method, and the warping degree or flatness evaluation of the target is tested according to a semiconductor substrate flatness testing method (such as a TTV thickness tester), or refers to a CN105806301A surface warping degree measuring device and method.

Example 1:

preparing gallium nitride powder: performing nitridation treatment on gallium oxide or gallium oxyhydroxide at 980 ℃ for 4 hours under the condition of ammonia gas to obtain gallium nitride powder, wherein the purity of the gallium oxide or the gallium oxyhydroxide is 99.995% or more, and the purity of the ammonia gas is 4N or more.

The grain size range of the prepared gallium nitride powder is 0.05-40 mu m, the purity is not lower than 99.995%, and the specific surface area is 3.6-18 m²/g。

Preparing a gallium nitride target material:

(1) grinding and screening the gallium nitride powder under the condition of carrier gas;

(2) adding 3 wt% of polyvinyl alcohol into the powder in the step (1), and pressing and forming the powder into a blank under the conditions of 100 ℃ and 90 MPa;

(3) and (3) pre-burning and binder removal are carried out on the blank in the step (2) at 600 ℃, and then sintering is carried out at 1000 ℃ under the condition of nitrogen to obtain the gallium nitride target. The obtained gallium nitride sintered body was structurally analyzed by X-ray diffraction into a gallium nitride phase, and the X-ray diffraction was as shown in FIG. 1.

According to the attached FIG. 2, the surface of the GaN target material is flat; by measuring the density and warpage of the target material, the density of the gallium nitride target material is not less than 60% of the theoretical density and reaches 3.6g/cm³～5.9g/cm³The flatness of the target material is less than 5 mu m, the gallium nitride sintered body is processed into a specified size according to the application, and the processing method can adopt a plane grinding method, a rolling circle grinding method, a linear cutting method, a laser cutting method, a chemical mechanical polishing method and other processing methods.

Example 2:

preparing zinc nitride powder: nitriding metallic zinc at 610 ℃ for 5 hours under the condition of ammonia gas to obtain zinc nitride powder, wherein the purity of the metallic zinc is 4N or more, and the purity of the ammonia gas is 4N or more.

The prepared zinc nitride powder has a particle size of 0.02-30 μm, a purity of 4N or above, and a specific surface area of 4.0-25 m²/g。

Preparing a zinc nitride target material:

(1) grinding and screening the zinc nitride powder under the condition of carrier gas;

(2) adding 1 wt% of polyvinyl alcohol into the powder in the step (1), and pressing and forming the powder into a blank under the conditions of 200 ℃ and 80 MPa;

(3) and (3) pre-burning and binder removal are carried out on the blank in the step (2) at 500 ℃, and then sintering is carried out at 650 ℃ under the nitrogen condition to obtain the zinc nitride target.

The surface of the zinc nitride target material is smooth; the density and the planeness of the target material are measured, and the density of the zinc nitride target material reaches 3.74g/cm³～6.20g/cm³The flatness of the target is less than 5 μm.

Example 3:

preparing indium nitride powder: performing nitridation treatment on indium oxide or indium oxyhydroxide at 680 ℃ for 3 hours under the condition of ammonia gas to obtain indium nitride powder, wherein the purity of the indium oxide or indium oxyhydroxide is 4N or more, and the purity of the ammonia gas is 4N or more.

The obtained indium nitride powder has particle diameter of 0.05-20 μm, purity of 4N or more, and specific surface area4.3 to 15m²/g

Preparing an indium nitride target material:

(1) grinding and screening the indium nitride powder under the condition of carrier gas;

(2) adding 5 wt% of polyvinyl alcohol into the powder in the step (1), and pressing and forming the powder into a blank under the conditions of 300 ℃ and 80 MPa;

(3) and (3) pre-burning and binder removal are carried out on the blank in the step (2) at 550 ℃, and then the blank is sintered at 600 ℃ under the ammonia gas condition to obtain the indium nitride target material.

The surface of the indium nitride target material is smooth; the density and the planeness of the target material are measured, and the density of the indium nitride target material reaches 4.30g/cm³～7.11g/cm³The flatness of the target is less than 10 μm.

The above-mentioned embodiments are merely preferred embodiments for fully illustrating the present invention, and the scope of the present invention is not limited thereto. The equivalent substitutions or changes made by the person skilled in the art on the basis of the present invention are all within the protection scope of the present invention. The protection scope of the invention is subject to the claims.

Claims

1. The preparation method of the nitride target is characterized by comprising the following steps of:

(1) under the condition of carrier gas, grinding and screening nitride powder;

(2) adding polyvinyl alcohol into the powder in the step (1), and performing pre-pressing molding in a mold by using cold isostatic pressing or hot isostatic pressing or warm isostatic pressing to form a blank;

(3) pre-burning the blank in the step (2) for glue discharging, and then performing 600-1000 times of glue discharging under the conditions of inert gas or ammonia gas or vacuum^oSintering at the temperature of C to obtain a nitride target material;

the nitride powder is prepared by the following method: the metal, metal oxide or metal oxyhydroxide corresponding to the nitride is treated at 600-980 ℃ under the condition of ammonia gas^oC, performing nitridation treatment for 2-7 hours to obtain nitride powder, wherein the purity of the oxide or the oxyhydroxide is not less than 99.995%, and the purity of ammonia gas is not less than 4N;

the nitride powder is gallium nitride powder, zinc nitride powder or indium nitride powder, and the metal, metal oxide or metal oxyhydroxide corresponding to the nitride is treated in the presence of ammonia gas at 600-^oC, performing nitriding treatment for 2-7 hours to obtain nitride powder, wherein the nitride powder comprises:

performing nitridation treatment on gallium oxide or hydroxyl gallium oxide at 980 ℃ for 4 hours under the condition of ammonia gas to obtain gallium nitride powder, wherein the particle size range of the prepared gallium nitride powder is 0.05-40 mu m, and the specific surface area is 3.6-18 m²(ii)/g; or

Nitriding metallic zinc at 610 ℃ for 5 hours under the condition of ammonia gas to obtain zinc nitride powder, wherein the particle size range of the prepared zinc nitride powder is 0.02-30 mu m, and the specific surface area is 4.0-25 m²(ii)/g; or

Performing nitridation treatment on indium oxide or indium oxyhydroxide at 680 ℃ for 3 hours under the condition of ammonia gas to obtain indium nitride powder, wherein the particle size range of the prepared indium nitride powder is 0.05-20 mu m, and the specific surface area is 4.3-15 m²/g；

And adding polyvinyl alcohol into the powder in the step (1), and pre-pressing and forming the powder into a blank in a mould by using cold isostatic pressing or hot isostatic pressing or warm isostatic pressing, wherein the step (1) comprises the following steps:

adding 3 wt% of polyvinyl alcohol into the gallium nitride powder, and pressing and forming the gallium nitride powder into a blank under the conditions of 100 ℃ and 90 MPa; or

Adding 1 wt% of polyvinyl alcohol into the zinc nitride powder, and pressing and forming the zinc nitride powder into a blank under the conditions of 200 ℃ and 80 MPa; or

Adding 5 wt% of polyvinyl alcohol into the indium nitride powder, and pressing and forming the indium nitride powder into a blank under the conditions of 300 ℃ and 80 MPa.

2. The method as claimed in claim 1, wherein the pre-burning glue-discharging temperature in step (3) is 500-^oC。

3. The production method according to claim 1, wherein in the step (3), the inert gas is nitrogen or argon.

4. A nitride target material prepared by the preparation method according to any one of claims 1 to 3.

5. Use of the nitride target according to claim 4 in semiconductor materials.