阅读说明：本技术 一种多孔钪氮化铝单晶材料、其制备方法及应用 (Porous scandium-aluminum nitride single crystal material, and preparation method and application thereof ) 是由 陈晨龙 蔡文汉 叶宁 颜涛 王俪霖 李俊谕 孙姝婧 于 2021-07-02 设计创作，主要内容包括：本申请公开了一种多孔钪氮化铝单晶材料及其制备方法、应用,所述多孔钪氮化铝单晶材料是多孔钪氮化铝单晶薄膜和/或多孔钪氮化铝单晶晶体；所述多孔钪氮化铝单晶晶体和所述多孔钪氮化铝单晶薄膜的尺寸为0.1cm～15cm。本发明是基于气相生长原理制备多孔钪氮化铝,通过调控制试验参数,获得低应力的无开裂的高质量多孔氮化铝体单晶。若以多孔钪氮化铝单晶作为钪氮化铝基器件的外延衬底,可以起到应力释放和减少位错的作用,比无孔钪氮化铝单晶衬底相比较,更具优势。该方法成本低,容易操作,易于重复。(The application discloses a porous scandium-aluminum nitride single crystal material, and a preparation method and application thereof, wherein the porous scandium-aluminum nitride single crystal material is a porous scandium-aluminum nitride single crystal film and/or a porous scandium-aluminum nitride single crystal; the sizes of the porous scandium aluminum nitride single crystal and the porous scandium aluminum nitride single crystal film are 0.1-15 cm. The invention prepares porous scandium aluminum nitride based on a vapor phase growth principle, and obtains a high-quality porous aluminum nitride body single crystal with low stress and no cracking by regulating and controlling test parameters. If the porous scandium-aluminum nitride single crystal is used as an epitaxial substrate of a scandium-aluminum nitride-based device, the effects of releasing stress and reducing dislocation can be achieved, and the scandium-aluminum nitride single crystal substrate has advantages compared with a non-porous scandium-aluminum nitride single crystal substrate. The method has low cost, easy operation and easy repetition.)

1. The porous scandium-aluminum nitride single crystal material is characterized in that the porous scandium-aluminum nitride single crystal material is a porous scandium-aluminum nitride single crystal thin film and/or a porous scandium-aluminum nitride single crystal;

the sizes of the porous scandium aluminum nitride single crystal and the porous scandium aluminum nitride single crystal film are 0.1-15 cm.

2. The porous scandium-aluminum nitride single crystal material according to claim 1, wherein the porous scandium-aluminum nitride single crystal material contains pores with a pore diameter of 10 to 2000 nm;

holes in the porous scandium-aluminum nitride single crystal material are three-dimensional communicating holes;

preferably, the pores in the porous scandium-aluminum nitride single crystal material are in a creeping shape.

3. The porous scandium-aluminum nitride single crystal material according to claim 1, wherein the thickness of the porous scandium-aluminum nitride single crystal thin film is 0.1 μm to 2 cm.

4. The porous scandium-aluminum nitride single crystal material according to claim 1, wherein the porous scandium-aluminum nitride single crystal material is a C-axis oriented porous scandium-aluminum nitride single crystal material;

preferably, the doping amount of scandium in the porous scandium aluminum nitride single crystal material is more than 0 and less than 60 wt%.

5. The porous scandium-aluminum nitride single crystal material according to claim 1, wherein the surface of the porous scandium-aluminum nitride single crystal thin film is a C-plane of a porous scandium-aluminum nitride single crystal;

the surface of the porous scandium-aluminum nitride single crystal is the C surface of the porous scandium-aluminum nitride single crystal.

6. A method for preparing a porous scandium aluminum nitride single crystal material according to any one of claims 1 to 5, wherein the method includes:

and carrying out contact reaction on the aluminum-containing compound single crystal material and the scandium-containing compound material in feed gas containing ammonia gas to obtain the porous scandium-aluminum nitride single crystal material.

7. The method as claimed in claim 6, wherein the reaction temperature is 800-1400 ℃; the pressure is 20-300 torr;

preferably, the aluminum compound-containing single crystal material includes at least one of a lithium aluminate single crystal and an alumina single crystal;

the scandium-containing compound material includes scandium oxide.

8. The method according to claim 6, wherein the reaction time is 10min to 100 hours.

9. The production method according to claim 6, characterized in that the feed gas containing ammonia gas further contains nitrogen gas and hydrogen gas;

preferably, in the feed gas containing ammonia gas,

the flow rate of the ammonia gas is marked as a, and a is more than or equal to 0.05SLM and less than or equal to 10 SLM;

the flow rate of the nitrogen is recorded as b, and b is more than or equal to 0SLM and less than or equal to 15 SLM;

the flow rate of the hydrogen is recorded as c, and c is more than or equal to 0SLM and less than or equal to 15 SLM;

preferably, the aluminum compound-containing single crystal material is contacted with the feed gas containing ammonia gas on the C face of the aluminum compound-containing single crystal material.

10. Use of at least one of the porous scandium aluminum nitride single crystal material according to any one of claims 1 to 5 and the porous scandium aluminum nitride single crystal material prepared by the method according to any one of claims 6 to 9 in the fields of surface acoustic wave devices and piezoelectric energy collectors.

Technical Field

The application relates to a porous scandium-aluminum nitride single crystal material, a preparation method and application thereof, belonging to the field of inorganic materials.

Background

Aluminum nitride (AlN) is an ultra-high temperature piezoelectric crystal (1150 ℃ C., up to 5.5 pc/N). Aluminum nitride and its related nitride materials are receiving increasing attention in energy harvesting devices, radio frequency devices and lead-free high temperature piezoelectric materials. In general, the higher the curie temperature of a piezoelectric material is, the lower the piezoelectric coefficient is, and it is difficult to balance between the use temperature and excellent piezoelectric performance. Scandium aluminum nitride is a piezoelectric semiconductor material with high dielectric strength, and research is just underway in terms of its availability in microelectronic applications. When the doped scandium concentration reaches 43%, the piezoelectric performance can reach 27.6 pC/N. Scandium (Sc) doped aluminum nitride (AlN) materials are widely used by a variety of devices, such as radio frequency filters, piezoelectric drivers, ultrasonic transducers, and the like. Studies have shown that ferroelectric switching behavior occurs in highly scandium-doped aluminum nitride films when the scandium content exceeds 30%. Research and development on scandium-aluminum nitride single crystal materials become a hotspot in the field of semiconductors, and the existing silicon-based elements are expected to be pushed to cross the performance limit.

The scandium aluminum nitride single crystal is generally grown mainly by magnetron sputtering. Since silicon has good conductivity and can be used to control the direction of crystal growth. Typically, single crystal silicon is selected for heteroepitaxy. However, due to the difference between the thermal expansion coefficients and unit cell parameters of the two substances, the heterogeneous nucleation can generate larger thermal mismatch and lattice mismatch, and stress is introduced in the crystal growth process, so that the surface of the crystal is cracked or a large number of micropores are generated. Such defects further degrade crystal quality in scandium aluminum nitride crystal growth, resulting in a large number of defects and even polycrystallization.

The existing method for preparing the nano porous material comprises a template method, a foaming method, a dealloying method, a Cokenter effect method, a resonance infiltration method and the like, the method is complex, the maximum crystal size capable of being prepared is only in the micrometer scale, and the macro-scale nano porous single crystal cannot be prepared. Therefore, it is necessary to provide a method for preparing a large-size nanoporous scandium aluminum nitride single crystal to provide a high-quality large-size nanoporous scandium aluminum nitride single crystal substrate and template for a scandium aluminum nitride-based device.

Disclosure of Invention

According to one aspect of the application, a porous scandium-aluminum nitride single crystal material is provided, the crystal structure is good, crystal grains grow along a c axis, the crystal surface morphology is excellent, and the propagation loss of surface acoustic waves can be reduced.

The invention prepares porous scandium aluminum nitride based on a vapor phase growth principle, and obtains a low-stress crack-free high-quality porous scandium aluminum nitride single crystal by regulating and controlling test parameters. If the porous scandium-aluminum nitride single crystal is used as an epitaxial substrate of a scandium-aluminum nitride-based device, the effects of releasing stress and reducing dislocation can be achieved, and the scandium-aluminum nitride single crystal substrate has advantages compared with a non-porous scandium-aluminum nitride single crystal substrate. The method has low cost, easy operation and easy repetition.

According to a first aspect of the application, a porous scandium aluminum nitride single crystal material is provided, wherein the porous scandium aluminum nitride single crystal material is a porous scandium aluminum nitride single crystal thin film and/or a porous scandium aluminum nitride single crystal;

the sizes of the porous scandium aluminum nitride single crystal and the porous scandium aluminum nitride single crystal film are 0.1-15 cm.

Optionally, the porous scandium-aluminum nitride single crystal material contains pores with the pore diameter of 10-2000 nm.

Optionally, the porous scandium-aluminum nitride single crystal material has an upper pore size limit independently selected from 2000nm, 1500nm, 1000nm, 500nm, 300nm, 100nm and a lower pore size limit independently selected from 10nm, 1500nm, 1000nm, 500nm, 300nm, 100 nm.

Optionally, the pores in the porous scandium-aluminum nitride single crystal material are three-dimensional interconnected pores.

Preferably, the pores in the porous scandium-aluminum nitride single crystal material are in a creeping shape.

Optionally, the thickness of the porous scandium-aluminum nitride single crystal thin film is 0.1 μm-2 cm.

Optionally, the porous scandium-aluminum nitride single crystal material is a C-axis oriented porous scandium-aluminum nitride single crystal material.

Optionally, the doping amount of scandium in the porous scandium aluminum nitride single crystal material is greater than 0 and less than 60 wt%.

Optionally, the surface of the porous scandium-aluminum nitride single crystal thin film is a C surface of the porous scandium-aluminum nitride single crystal;

the surface of the porous scandium-aluminum nitride single crystal is the C surface of the porous scandium-aluminum nitride single crystal.

According to a second aspect of the application, a preparation method of the porous scandium-aluminum nitride single crystal material is provided, and the method comprises the following steps:

and carrying out contact reaction on the aluminum-containing compound single crystal material and the scandium-containing compound material in feed gas containing ammonia gas to obtain the porous scandium-aluminum nitride single crystal material.

Preferably, the aluminum compound-containing single crystal material includes at least one of a lithium aluminate single crystal and an alumina single crystal;

the scandium-containing compound material includes scandium oxide.

Optionally, the reaction temperature is 800-1400 ℃; the pressure is 20-300 torr.

Alternatively, the upper limit of the reaction temperature is independently selected from 1400 ℃, 1300 ℃, 1200 ℃, 1100 ℃, 1000 ℃, 900 ℃, and the lower limit is independently selected from 800 ℃, 900 ℃, 1000 ℃, 1100 ℃, 1200 ℃, 1300 ℃.

Alternatively, the upper reaction pressure limit is independently selected from 300torr, 250 torr, 200 torr, 150 torr, 100 torr, 50 torr, and the lower limit is independently selected from 20 torr, 250 torr, 200 torr, 150 torr, 100 torr, 50 torr.

Optionally, the contact reaction time of the aluminum-containing compound single crystal material and the scandium-containing compound material with the feed gas containing ammonia gas is 10min to 100 h.

In one embodiment, when the porous scandium-containing aluminum nitride single crystal material is a porous scandium-containing aluminum nitride single crystal thin film, the contact reaction time of the aluminum-containing compound single crystal material and the scandium-containing compound material with the feed gas containing ammonia gas is 10min to 48 h. The length of the reaction time is positively correlated with the thickness of the porous scandium-aluminum nitride single-crystal film, and the longer the contact reaction time is, the larger the thickness of the obtained porous scandium-aluminum nitride single-crystal film is.

Preferably, when the porous scandium aluminum nitride single crystal material is a porous scandium aluminum nitride single crystal thin film, the lower limit of the time range of the contact reaction of the lithium aluminate single crystal material and the feed gas containing ammonia gas is selected from 10min, 5h, 15h, 25h, 35h and 45h, and the upper limit is selected from 48h, 38h, 28h, 18h, 8h or 1 h.

When the prepared porous scandium-aluminum nitride single crystal material is a porous scandium-aluminum nitride single crystal, the contact reaction time is required to ensure that the aluminum-containing compound single crystal material is completely converted into the porous scandium-aluminum nitride single crystal material. In one embodiment, when the porous scandium aluminum nitride single crystal material is a porous scandium aluminum nitride single crystal, the contact reaction time of the aluminum-containing compound single crystal material and a feed gas containing ammonia gas is 0.5h to 100 h. One skilled in the art can determine the appropriate contact reaction time based on the actual requirements and the size of the single crystal material of the aluminum-containing compound to be used. Preferably, when the porous scandium aluminum nitride single crystal material is a porous scandium aluminum nitride single crystal, the lower limit of the time range of the contact reaction of the aluminum-containing compound single crystal material and the feed gas containing ammonia gas is selected from 0.5h, 15h, 35h, 55h, 75h or 95h, and the upper limit is selected from 100h, 80h, 60h, 40h, 20h or 10 h.

By adopting the method provided by the application, the crystal size of the obtained porous scandium-aluminum nitride single crystal is equal to that of the aluminum-containing compound single crystal material. The skilled person can select an appropriate size of the aluminum-containing compound single crystal material according to actual needs to obtain the desired porous scandium-aluminum nitride single crystal.

Optionally, the feed gas containing ammonia also contains nitrogen and hydrogen.

Alternatively, in the feed gas containing ammonia gas,

the flow rate of the ammonia gas is marked as a, and a is more than or equal to 0.05SLM and less than or equal to 10 SLM;

the flow rate of the nitrogen is recorded as b, and b is more than or equal to 0SLM and less than or equal to 15 SLM;

the flow rate of the hydrogen is recorded as c, and c is more than or equal to 0SLM and less than or equal to 5 SLM.

Optionally, the aluminum compound-containing single crystal material is contacted with a feed gas containing ammonia gas on the C face of the aluminum compound-containing single crystal.

Optionally, the preparation method comprises:

(1) according to the experimental requirements, the parts of devices required by the experiment, such as a vacuum gauge, a pressure gauge, a ceramic tube with proper size and the like, are self-assembled.

(2) A piece of 1cm × 1cm (001) plane lithium aluminate single crystal was placed in an ethanol solution, ultrasonic-cleaned for 10 minutes, then cleaned with deionized water, and purged with a nitrogen gun.

(3) Weighing 0.5g of scandium oxide powder as a raw material, putting the scandium oxide powder into a ceramic boat, putting a clean lithium aluminate single crystal above the scandium oxide powder, then putting the whole ceramic boat into a furnace body constant temperature area, closing a furnace cover, carrying out vacuum-pumping treatment, filling a proper amount of nitrogen after vacuum-pumping to the limit, vacuumizing again until the pressure in the furnace body is pumped to 4.0 multiplied by 10^-3Torr。

The pressure in the furnace was controlled to 300Torr by introducing a raw material gas containing ammonia as a main mixed gas, (ammonia flow: 1slm, nitrogen flow: 0.5slm, hydrogen flow: 0.3 slm). The temperature was raised to 1100 deg.C at a rate of 5 deg.C/min (at which time 0.3slm hydrogen flow was introduced). And growing for 30 h. So that the lithium aluminate is fully mixed with the scandium oxide and the raw material gas, and a layer of brown scandium aluminum nitride grows on the substrate. After the reaction was completed sufficiently, 0.2slm of argon was introduced and the temperature was lowered to room temperature at a rate of 5 ℃/min. And the sample was removed.

According to the final aspect of the application, at least one of the porous scandium aluminum nitride single crystal material and the porous scandium aluminum nitride single crystal material prepared by the method is applied to the fields of surface acoustic wave devices and piezoelectric energy collectors.

The invention discloses a preparation method for preparing a highly C-axis oriented porous scandium aluminum nitride single crystal material and reducing process difficulty, and particularly relates to a method for preparing porous scandium aluminum nitride based on a vapor phase growth principle. The crystal structure is good, crystal grains grow along the c axis, the surface appearance of the crystal is excellent, and the propagation loss of surface acoustic waves can be reduced; the film has higher resistivity and lower leakage current, so the insulating property is good. The piezoelectric film prepared by the invention has application prospect in the fields of surface acoustic wave devices and piezoelectric energy collectors.

In the present application, SLM is an abbreviation of Standard Litre Per Minute, and indicates a flow rate of 1L/min in a Standard state.

In this application, the size of a single crystal refers to the distance between two farthest points on the surface of the crystal having the largest area.

The size of the single crystal thin film refers to the distance between two points adjacent to the farthest point on the plane having the largest area.

Benefits of the present application include, but are not limited to:

(1) the porous scandium-aluminum nitride single crystal material provided by the application reports a large-size polar (0001) C-plane porous scandium-aluminum nitride single crystal for the first time.

(2) According to the preparation method of the porous scandium-aluminum nitride single crystal material, the aluminum-containing compound single crystal material, scandium-aluminum nitride crystal and ammonia gas are subjected to outward and inward nitridation conversion and reverse epitaxial growth at high temperature by utilizing the characteristics that the aluminum-containing compound single crystal material and the scandium-aluminum nitride crystal are similar in structure and are matched in crystal lattices, and other products are completely volatilized.

(3) The preparation method of the porous scandium-containing aluminum nitride single crystal material can regulate and control the doping amount of scandium element by controlling the distance between a scandium-containing compound material and an aluminum-containing compound single crystal material, the reaction temperature and the like, and provides more application possibilities for the porous scandium-containing aluminum nitride single crystal.

(4) The preparation method of the porous scandium-aluminum nitride single crystal material is simple to operate, good in repeatability, low in cost and suitable for large-scale industrial production.

Drawings

Fig. 1 is a photograph of a sample # 1 porous scandium aluminum nitride single crystal.

Fig. 2 is a scanning electron microscope plan photograph of a sample 1# polar (0001) C-plane porous scandium aluminum nitride single crystal.

Fig. 3 is a scanning electron micrograph of a1# polar (0001) C-plane porous scandium aluminum nitride single crystal of sample.

Fig. 4 shows the X-ray diffraction results of the sample 1# polar (0001) C-plane porous scandium aluminum nitride single crystal thin film.

Detailed Description

The present application will be described in detail with reference to examples, but the present application is not limited to these examples.

In the examples, X-ray diffraction analysis of the samples was carried out using Miniflex 600, Cu K.alpha.Rigaku corporation (Cu-K.alpha.1 radiation; operated at 40kV and 45 mA;) A high resolution X-ray diffraction analyzer. The element content analysis adopts an ESCALAB 250Xi type X-ray photoelectron spectrometer

Example 1

Taking a (0001) surface lithium aluminate single crystal wafer with the size of 0.5cm as a substrate, placing the substrate in a ceramic boat filled with scandium oxide powder, then placing the substrate in a ceramic reactor, introducing feed gas containing ammonia (the feed gas consists of ammonia, nitrogen and hydrogen, namely ammonia 2SLM, nitrogen 0.5SLM and hydrogen 0.1SLM), heating the system to 1000 ℃, keeping the system pressure at 300torr, reacting for 24 hours, and cooling to room temperature to obtain a porous scandium-aluminum nitride single crystal film sample, wherein the film thickness is 150nm and is marked as sample A1 #.

Taking a (0001) surface lithium aluminate single crystal wafer with the size of 0.5cm as a substrate, placing the substrate in a ceramic boat filled with scandium oxide powder, then placing the substrate in a ceramic reactor, introducing a feed gas containing ammonia (the feed gas consists of ammonia, nitrogen and hydrogen, and the ammonia is 2SLM, 0.5SLM and 0.1SLM), heating the system to 1000 ℃, keeping the system pressure at 300torr, reacting for 100 hours, and cooling to room temperature to obtain a porous scandium aluminum nitride single crystal sample, wherein the sample is marked as sample No. 1, the crystal size of the sample No. 1 is 0.5cm, and the scandium content is 1 wt%. FIG. 1 is a photograph of a crystal of sample # 1 porous scandium aluminum nitride single crystal, from which it is seen that the crystal size is about 0.5 cm. Fig. 2 is a scanning electron microscope planar photograph of a sample 1# polar (0001) C-plane porous scandium-aluminum nitride single crystal, from which it can be seen that pores with a size of about 50nm trepanning structure are uniformly distributed on the surface. FIG. 3 is a scanning electron micrograph of a1# polar (0001) C-plane porous scandium aluminum nitride single crystal, and it can be seen that the thickness is about 2 μm. Fig. 4 shows the X-ray diffraction results of the sample 1# polar (0001) C-plane porous scandium aluminum nitride single crystal thin film, which is a single crystal and has good crystal quality.

Examples 2 to 3

Preparation of a porous scandium-aluminum nitride single crystal material: compared to example 1, the only difference is as shown in table 1:

TABLE 1 differences between the preparation methods of examples 2 to 3 and example 1

Raw materials/conditions/parameters	Example 1(A1#)	Example 2(A2#)	Example 3(A3#)
				Host crystal	Lithium aluminate crystal	Alumina crystal	Lithium aluminate crystal
Flow rate of ammonia gas	2slm	5slm	10slm
				Size of substrate	0.5cm	1cm	3cm
Constant temperature	1000℃	800℃	1400℃
				Constant temperature time	24h	100h	0.5h
Constant temperature pressure	300Torr	100Torr	20Torr

The scandium content in sample A2# was 25 wt%, and the scandium content in sample A3# was 56 wt%.

Example 4 measurement of piezoelectric Properties

And (3) determining a sample: 1#

The determination method comprises the following steps: the samples were subjected to D33 testing by a piezo-responsive microscope (Dimension ICON).

Test results and analysis: the piezoelectric response test was performed on sample # 1. In the voltage range from-10V to +10V, the scanning area is 2 um' 2um, an experimental spectrogram shows that a butterfly curve with obvious 180-degree phase reversal and amplitude reversal exists, and the D33 value is calculated to be about 60pm/V, so that excellent piezoelectric performance is shown.

Although the present application has been described with reference to a few embodiments, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the application as defined by the appended claims.