Method for performing (100) crystal face dislocation kinetic research based on nanoindentation

Abstract

The invention belongs to the technical field of semiconductor crystals, and particularly relates to a nanoindentation-based (100) crystal face dislocation kinetic research method. The method comprises the following steps: aligning an indenter of a nanoindenter with a crystal face (100) of a sample to carry out indentation treatment, and introducing dislocation in the sample through indentation treatment to obtain a nanoindented sample; performing corrosion treatment on the sample subjected to nanoindentation treatment, and performing corrosion on a (100) crystal face to obtain a dislocation line; and (100) crystal face dislocation kinetic research is carried out according to the (100) crystal face dislocation line. The device has the advantages of small test area, small sample damage and capability of accurately controlling load and displacement, and meanwhile, a clear dislocation line can be obtained through corrosion treatment. According to the method provided by the invention, the problems of complicated equipment, high cost, low observation and measurement precision and the like in the prior art are solved, and the in-depth and accurate research on the dislocation kinetics in the [010] direction of the beta-Ga2O3 (100) crystal face is realized.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of semiconductor crystals, and particularly relates to a method for studying (100) crystal face dislocation dynamics based on nanoindentation. BACKGROUND

[0002] The fourth generation semiconductor material β-Ga2O3 is concerned due to its super-wide band gap of 4.8 eV, high critical breakdown field of 8 MV / cm and optical absorption edge of nearly 260 nm. Ga2O3 has five polymorphs, and only the β phase with high thermodynamic stability can remain stable throughout the heating stage until the melting point (about 1800℃), while other polymorphs are metastable and spontaneously convert to β-Ga2O3 above 870℃. Due to its asymmetric monoclinic crystal structure, different characteristic crystal planes have anisotropy. Among these planes, the (100) plane is easy to process as the main cleavage plane and has excellent chemical stability, making it the best interface for crystal size amplification.

[0003] Among the numerous crystal planes of β-Ga2O3, the (100) crystal plane is the preferred substrate or epitaxial surface for preparing high-performance β-Ga2O3 devices due to its good surface stability, low surface energy, and good compatibility with device preparation processes such as epitaxial growth and electrode preparation. However, dislocations, as common linear defects in β-Ga2O3 crystals, have a significant impact on the mechanical properties, electrical properties and device reliability. Specifically, dislocations can cause an increase in device leakage current, a decrease in breakdown field strength, and a decrease in carrier mobility, and can accelerate the degradation of device reliability, severely restricting the improvement of β-Ga2O3 device performance and the actual application process.

[0004] Therefore, in-depth study of the dynamic behavior of β-Ga2O3 (100) crystal plane dislocations, including dislocation motion, proliferation, and interaction, is of great significance for understanding the influence mechanism of dislocations on material and device performance, optimizing material preparation processes, and improving device reliability.

[0005] However, in current research, the study of β-Ga2O3 (100) crystal plane dislocation dynamics faces many challenges. Existing research methods have obvious limitations. Some methods rely on large, expensive and complex special equipment such as high-resolution transmission electron microscopes, which not only greatly increases the research cost but also raises the experimental operation threshold, making it difficult to widely carry out systematic research. At the same time, the sample preparation process of these methods is often extremely complicated, requiring multiple complex procedures, taking a long time, and easily introducing new defects during the preparation process, interfering with the accuracy of the experimental results.

[0006] At present, the observation of gallium oxide dislocation is mainly through focused ion beam technology (FIB) sample preparation, and then using transmission electron microscope (TEM) for observation. However, due to the limitation of focused ion beam sample preparation, the length of the prepared sample may be much smaller than the length of the dislocation expansion, and therefore, due to the limitation of the sample size, it is difficult to observe the complete dislocation slip length by transmission electron microscope, and it is difficult to conduct in-depth and accurate research on the

[010] direction dislocation. SUMMARY

[0007] The purpose of the present application is to provide a method for studying the dislocation dynamics of the (100) crystal plane based on nanoindentation. The method provided by the present application can effectively measure the length of dislocation slip, and can accurately, efficiently and low-costly study the dislocation dynamics of the (100) crystal plane of beta-Ga2O3, which has important significance for the technological progress and industrial development of the gallium oxide industry.

[0008] In order to achieve the above purpose, the present application provides the following technical scheme:

[0009] The present application provides a method for obtaining a (100) crystal plane dislocation line based on nanoindentation, comprising the following steps:

[0010] (1) Aligning the indenter of the nanoindenter to the (100) crystal plane of the sample for indentation treatment, introducing dislocation in the sample by indentation treatment, and obtaining a nanoindentation treated sample;

[0011] (2) Corrosion treatment of the nanoindentation treated sample to obtain a dislocation line on the (100) crystal plane.

[0012] Preferably, in step (1), the sample is beta-Ga2O3 with a (100) crystal plane.

[0013] Preferably, in step (1), the indenter is a diamond indenter; and the indentation treatment conditions include: loading load of 5-100 mN, loading rate of 0.1-1 mN / s, holding time of 10-60 s, and unloading rate of 0.1-1 mN / s.

[0014] Preferably, in step (1), the dislocation is a dislocation slipping along the

[010] direction; and in step (2), the dislocation line is a dislocation line along the

[010] direction.

[0015] Preferably, in step (2), the corrosion treatment includes wet chemical etching, dry etching or photoelectrochemical etching.

[0016] Preferably, the wet chemical etching includes acid solution etching, alkali solution etching or molten alkali etching; the acid solution etching uses phosphoric acid solution as the etching reagent, and the etching temperature is greater than or equal to 130 DEG C; the alkali solution etching uses KOH solution as the etching reagent, and the etching temperature is 100-110 DEG C; the molten alkali etching uses molten KOH and / or molten NaOH as the etching reagent, and the etching temperature is greater than or equal to 200 DEG C.

[0017] Preferably, the mass content of KOH in the KOH solution is 20-40 wt%; and the alkali solution etching time is 30-180 min.

[0018] Preferably, after obtaining the nano-indentation treated sample, before the etching treatment, the nano-indentation treated sample is further subjected to annealing treatment, the annealing temperature is room temperature-1200 DEG C, and the holding time is 30-60 s.

[0019] In step (2), after obtaining the dislocation line, the information of the dislocation line is recorded and measured by using differential interference microscopy, and the information includes the length of the dislocation line.

[0020] The present application provides a method for studying the (100) crystal plane dislocation kinetics based on nano-indentation, wherein the (100) crystal plane dislocation line is obtained according to the above technical solution; and the (100) crystal plane dislocation kinetics is studied according to the (100) crystal plane dislocation line.

[0021] Preferably, the (100) crystal plane dislocation kinetics includes the corresponding relationship between the length of the (100) crystal plane dislocation line and the peak load of the indentation treatment, the corresponding relationship between the length of the extra dislocation slip and the annealing temperature of the annealing treatment after the indentation treatment, and the corresponding relationship between the dislocation velocity and the annealing temperature of the annealing treatment after the indentation treatment.

[0022] The present application provides a method for obtaining a (100) crystal plane dislocation line based on nano-indentation, which includes the following steps: (1) aiming the indenter of a nano-indenter at the (100) crystal plane of a sample to perform indentation treatment, introducing dislocations in the sample by the indentation treatment, and obtaining a nano-indentation treated sample; and (2) etching the nano-indentation treated sample to obtain a dislocation line on the (100) crystal plane. The present application provides a method for studying the (100) crystal plane dislocation kinetics based on nano-indentation, wherein the (100) crystal plane dislocation line is obtained according to the above technical solution; and the (100) crystal plane dislocation kinetics is studied according to the (100) crystal plane dislocation line. The dislocation of the (100) plane of β-Ga2O3 is a key defect affecting the performance of devices, and its type, density and distribution are closely dependent on the crystal growth process and material quality. Compared with the prior art, the present application has the following beneficial effects:

[0023] The existing method often cannot clearly present the morphology of dislocation lines, the precision of the measuring tool is limited, so that the data of dislocation line length and the like obtained have large errors, the dynamics characteristics of dislocation cannot be accurately reflected, and further the analysis of the laws of dislocation movement and proliferation is affected. The present application adopts the nano indentation technology, the pressure control precision is high, the present application uses the nano indentation to damage the crystal structure, and further artificially introduces defects. The research of the present application shows that when the nano indentation is carried out on the (100) surface of beta-Ga2O3, defects such as layer dislocation and dislocation are generated, and the dislocation is expanded in the <010> / {001} slip system.

[0024] The present application adopts the nano indentation technology, has the advantages of small test area, small sample damage, precise control of load and displacement, and simultaneously, the present application can corrode to obtain clear dislocation lines by adopting the corrosion treatment. The method proposed in the present application solves the problems of complex equipment, high cost, low observation and measurement precision and the like in the prior art, realizes the in-depth and precise research on the dynamics of the

[010] direction dislocation of the (100) crystal surface of beta-Ga2O3, and provides strong technical support for promoting the development of beta-Ga2O3 materials and devices.

[0025] Further, in the present application, the corrosion treatment is alkali solution corrosion, and the length of the dislocation line is recorded and measured by using the differential interference microscope. The alkali solution corrosion used in the present application can selectively corrode the dislocation line, and the differential interference microscope can realize high-precision observation and measurement, so as to improve the accuracy of the research results of the dynamics of the (100) crystal surface dislocation. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The corrosion pit morphology under the loading load of 10 mN;

[0027] Figure 2 The corrosion pit morphology under the loading load of 30 mN;

[0028] Figure 3 The corrosion pit morphology under the loading load of 50 mN;

[0029] Figure 4 The experimental data and fitting curve of l0 and P 1 / 2

[0030] Figure 5 The dislocation lines after annealing at room temperature and 300, 600, 900 and 1200 DEG C respectively under the peak load of 30 mN and 100 mN;

[0031] Figure 6 The dependence of l T on temperature and the fitting curve thereof;

[0032] Figure 7 ​The relationship between dislocation velocity and temperature and the fitting curve thereof;

[0033] Figure 8 The etch pit morphology of the Sn-doped sample;

[0034] Figure 9 The etch pit morphology of the Fe-doped sample. DETAILED DESCRIPTION

[0035] The present application provides a method for obtaining (100) dislocation lines based on nanoindentation, comprising the following steps:

[0036] (1) The indenter of the nanoindenter is aligned with the (100) crystal plane of the sample for indentation treatment, and dislocations are introduced into the sample by the indentation treatment to obtain a nanoindentation-treated sample;

[0037] (2) The nanoindentation-treated sample is subjected to etching treatment to obtain dislocation lines on the (100) crystal plane.

[0038] In the present application, all the preparation raw materials / components are commercially available products well known to those skilled in the art unless otherwise specified.

[0039] In the present application, the indenter of the nanoindenter is aligned with the (100) crystal plane of the sample for indentation treatment, and dislocations are introduced into the sample by the indentation treatment to obtain a nanoindentation-treated sample.

[0040] In the present application, the sample is preferably β-Ga2O3 with a (100) crystal plane. The β-Ga2O3 with a (100) crystal plane can be doped β-Ga2O3 with a (100) crystal plane or unintentionally doped (UID) β-Ga2O3 with a (100) crystal plane. The doped β-Ga2O3 with a (100) crystal plane can be Sn or Fe-doped β-Ga2O3 with a (100) crystal plane.

[0041] In the present application, the sample is preferably pretreated before the indentation treatment. The pretreatment preferably comprises cleaning and drying in sequence. The reagent used for cleaning is preferably one or more of water, acetone, isopropanol and anhydrous ethanol. The water is preferably deionized water. The present application preferably removes impurities and contaminants on the surface of the sample by cleaning. In a specific embodiment of the present application, the cleaning can comprise the following steps: placing the sample in water for cleaning, and then sequentially using acetone, isopropanol and anhydrous ethanol for ultrasonic cleaning. The drying is preferably performed by using an air gun. The present application preferably stores the pretreated sample in a clean adsorption box.

[0042] The sample is preferably fixed on a sample stage of a nanoindenter, and a pressure head of the nanoindenter is adjusted to align with the (100) crystal surface of the sample.

[0043] In the present application, the pressure head is preferably a diamond pressure head, and in an embodiment, can be a diamond Berkovich pressure head.

[0044] In the present application, the conditions of the indentation treatment preferably include: the loading load is preferably 5-100 mN, and in an embodiment, can be 10 mN, 30 mN, 50 mN, 60 mN, 70 mN, 80 mN, 90 mN or 100 mN; the loading rate is preferably 0.1-1 mN / s, and in an embodiment, can be 0.2 mN / s, 0.3 mN / s, 0.4 mN / s, 0.5 mN / s, 0.6 mN / s, 0.7 mN / s, 0.8 mN / s, 0.9 mN / s or 1 mN / s; the holding time is preferably 10-60 s, and in an embodiment, can be 10 s, 20 s, 30 s, 40 s, 50 s or 60 s; and the unloading rate is preferably 0.1-1 mN / s, and in an embodiment, can be 0.2 mN / s, 0.3 mN / s, 0.4 mN / s, 0.5 mN / s, 0.6 mN / s, 0.7 mN / s, 0.8 mN / s, 0.9 mN / s or 1 mN / s.

[0045] In the present application, the dislocation can be a dislocation slipping along the

[010] direction.

[0046] After obtaining the nanoindented sample, the nanoindented sample is subjected to etching treatment to obtain dislocation lines on the (100) crystal surface.

[0047] In the present application, after obtaining the nanoindented sample, the nanoindented sample is preferably subjected to annealing treatment before the etching treatment, and the annealing treatment is preferably at a temperature of room temperature-1200℃, and in an embodiment, can be at room temperature (15-30℃), 300℃, 600℃, 900℃ or 1200℃. The holding time of the annealing treatment is preferably 30-60 s, and in an embodiment, can be 60 s. The heating rate of the annealing treatment is preferably 80-100℃ / s. Compared with room temperature annealing treatment, annealing treatment at 300-1200℃ is "high-temperature" annealing. Since a semiconductor crystal sample is only approximately stable at absolute zero, room temperature is also an annealing temperature relative to the absolute zero. However, through experimental research, it is found that the experimental phenomenon of room temperature annealing treatment is not significant.

[0048] The annealing sample obtained through the annealing treatment is preferably subjected to the etching treatment.

[0049] In the present application, the etching treatment preferably comprises wet chemical etching, dry etching or photoelectrochemical etching. The wet chemical etching preferably comprises acid solution etching, alkali solution etching or molten alkali etching. The acid solution etching preferably uses phosphoric acid solution as the etching reagent, and the etching temperature is preferably ≥ 130℃. The alkali solution etching preferably uses KOH solution as the etching reagent, and the etching temperature is preferably 100-110℃. The molten alkali etching preferably uses molten KOH and / or NaOH as the etching reagent, and the etching temperature is preferably ≥ 200℃.

[0050] In the present application, the etching treatment is preferably alkali solution etching. The mass content of KOH in the KOH solution is preferably 20-40wt%. The temperature of the alkali solution etching can be 100℃, 105℃ or 110℃. The time of the alkali solution etching is 30-180min, and in the examples can be 30min, 40min, 50min, 60min, 120min or 180min. During the etching process, the alkali solution preferentially etches the region where the dislocation line is located, thereby etching a dislocation line on the sample surface.

[0051] In the present application, after the etching treatment, the present application preferably performs cleaning and drying on the obtained sample after etching treatment. The reagent used in the cleaning preferably comprises water and anhydrous ethanol. The water is preferably deionized water. The drying is preferably air drying.

[0052] In the present application, the dislocation line is preferably a dislocation line slipping along the

[010] direction.

[0053] In the present application, after obtaining the dislocation line, the present application further comprises recording and measuring the information of the dislocation line by differential interference microscopy. The information preferably comprises the length of the dislocation line.

[0054] The present application provides a method for studying (100) crystal plane dislocation dynamics based on nanoindentation, wherein a (100) crystal plane dislocation line is obtained according to the method described in the above technical solution; and (100) crystal plane dislocation dynamics is studied according to the (100) crystal plane dislocation line.

[0055] The present application obtains the information of the (100) crystal plane dislocation line under different conditions by changing the parameters of the indentation treatment (including loading load, loading rate, holding time and unloading rate) and repeating the above method. The information of the (100) crystal plane dislocation line under different conditions comprises the length of the (100) crystal plane dislocation line under different conditions.

[0056] According to the information of the (100) crystal plane dislocation line under different conditions, the present application analyzes the kinetic behaviors such as motion and multiplication of dislocations, and studies the influence of different factors on dislocation kinetics.

[0057] In the present application, the (100) crystal plane dislocation dynamics research includes: the corresponding relationship between the length of the (100) crystal plane dislocation line and the peak load of the indentation treatment, the corresponding relationship between the length of the additional dislocation slip and the annealing temperature of the annealing treatment after the indentation treatment, and the corresponding relationship between the dislocation velocity and the annealing temperature of the annealing treatment after the indentation treatment.

[0058] In the present application, the length of the additional dislocation slip is the length of the additional dislocation slip caused by the release of residual stress under different annealing temperature conditions compared with no annealing treatment.

[0059] In summary, the present application precisely introduces dislocations in the

[010] direction of the (100) crystal plane of β-Ga2O3 by nanoindentation technology, and realizes clear presentation and accurate measurement of dislocation lines by combining alkali solution etching development and differential interference microscope observation measurement. On this basis, the present application systematically studies the influence of different factors on the dislocation dynamics by changing the experimental parameters, so as to obtain the key dynamic parameters such as the movement rate, proliferation rule and interaction of the dislocations in the (100) crystal plane of β-Ga2O3. The present application provides reliable experimental methods and data support for in-depth understanding of the behavior mechanism of the dislocations in the (100) crystal plane of β-Ga2O3, and further lays a solid theoretical and experimental foundation for optimizing the preparation process of β-Ga2O3 material and improving the performance and reliability of devices.

[0060] In order to further illustrate the present application, the technical solutions provided by the present application will be described in detail below in conjunction with examples, but they should not be understood as limiting the scope of protection of the present application.

[0061] Example 1

[0062] 1. Select a β-Ga2O3 (100) crystal plane sample with a smooth surface, and clean the surface of the sample to remove impurities and contaminants. The cleaning steps include: placing the β-Ga2O3 (100) crystal plane sample (gallium oxide wafer) in deionized water for cleaning, then sequentially using acetone, isopropanol and anhydrous ethanol for ultrasonic cleaning, drying with an air gun after cleaning, and then storing in a clean adsorption box.

[0063] 2. Introducing dislocations by nanoindentation: Fix the β-Ga2O3(100) wafer sample treated in step 1 on the sample stage of the nanoindenter, and adjust the indenter of the nanoindenter to align with the (100) surface of the sample. Set the parameters of the nanoindenter, including the indenter type - diamond Berkovich indenter, the loading range of 5-100 mN (10 mN in this example), the loading rate of 0.1-1 mN / s (1 mN / s in this example), the holding time of 10-60 s (30 s in this example), and the unloading rate of 0.1-1 mN / s (1 mN / s in this example). Start the nanoindenter to perform indentation on the β-Ga2O3(100) surface, and introduce dislocations in the

[010] direction in the sample.

[0064] 3. Etching and developing the dislocation lines by alkaline solution: Put the sample treated by nanoindentation in step 2 into a container containing alkaline solution for etching. The alkaline solution is a KOH solution with a mass content of 30 wt%, the etching temperature is 110°C, and the etching time is 60 minutes. During the etching process, the alkaline solution preferentially etches the area where the dislocation lines are located, thereby etching a dislocation line in the

[010] direction on the surface of the sample.

[0065] 4. Observation and length measurement of the dislocation lines: After etching, take the sample out of the alkaline solution, clean it with deionized water and anhydrous ethanol, and dry it. Use a differential interference microscope to observe the surface of the sample and find the dislocation line etched in the

[010] direction. Record and measure the length of the dislocation line by the differential interference microscope.

[0066] Figure 1 For the etching pit morphology of the 10 mN loading load in Example 1, a large number of etching pits can be seen on the surface of the sample under a 500x optical microscope, wherein the nanoindentation etching pit is long strip-shaped, the long side is in the

[010] direction, and the tail is also in the

[010] direction, and the tail length is the dislocation slip length.

[0067] 5. Dislocation dynamics research: This example changes the parameters of the nanoindentation (such as loading load, loading rate, holding time, unloading rate, etc.), repeats steps 2-4 above, and obtains the length of the dislocation line under different conditions. According to these data, analyze the motion and proliferation dynamics of dislocations, and study the influence of different factors on the dynamics of dislocations.

[0068] Example 2

[0069] The method provided in Example 1 is basically the same, except that the loading load in this example is 30 mN.

[0070] Figure 2For the etch pit morphology under 30 mN loading in Example 2, the long axis of the tailing along the

[010] direction can be seen under 500 times optical microscope, and the dislocation slip length (tailing length) can be measured as 81 μm.

[0071] Example 3

[0072] The method provided in Example 1 is basically the same, except that the loading in this example is 50 mN.

[0073] Figure 3 For the etch pit morphology under 50 mN loading in Example 3, the morphology of the hexagonal etch pit with tailing can be distinguished from the numerous etch pits under 500 times optical microscope, thus the etch pit morphology of the nanoindentation can be determined, and the conversion of the dislocation slip length measurement can be realized by measuring the length of the tailing.

[0074] Example 4

[0075] In this example, the dislocation line length at room temperature under the stress field caused by the indentation under different loadings, i.e. the dislocation slip length (lo), is analyzed, so as to obtain the relationship between the movement distance of the dislocation and the loading condition. The relationship can be expressed as formula (1):

[0076]

[0077] Wherein, C and m are material parameters, t represents the holding time of the indenter, and P represents the peak load of the nanoindentation. lo and P 1 / 2 are linearly correlated. The present application draws the function graph of lo and P 1 / 2 and the corresponding fitting results, as Figure 4 . Figure 4 the experimental data and the fitting curve of lo and P 1 / 2 .

[0078] As can be seen from Figure 4 , lo and P 1 / 2 are in good linear relationship as expected. In addition, the fitted curve does not pass through the coordinate origin, and the intersection point on the horizontal coordinate is calculated as 0.32 mN, which can be considered as the position where the dislocation starts to form and expand.

[0079] At room temperature, not only does the nanoindenter form an indentation on the sample surface, but during this process the indenter also introduces a high density of dislocations around the indentation, and a stress field is formed around the indentation by the indenter. For structures in which dislocations are easy to slip, such as β-Ga2O3 crystals, the stress will push the dislocations to slip away from the indentation location until the dislocations reach the farthest end when the stress at the front end of the dislocations and the critical shear stress are balanced. When the indenter is removed, a certain amount of residual stress is still present in the area around the indentation. When the temperature of the sample is increased, the critical shear stress decreases, the balance between the residual stress and the critical shear stress is broken, and the residual stress drives the dislocations to slip away from the indentation until a new balance position is reached, so that the new residual stress is again balanced with the critical shear stress at this temperature.

[0080] Figure 5 The statistical length of the dislocation lines was measured after nanoindentation at a peak load of 30 mN and 100 mN, respectively, followed by annealing at room temperature (25°C), 300, 600, 900, and 1200°C (the holding time was 60 s), and finally chemical etching.

[0081] Figure 5 The statistical length of the dislocation lines at different annealing temperatures is shown for peak loads of 30 mN and 100 mN (the dislocation lines obtained at a peak load of 100 mN, and the other operating parameters are the same as in Example 2). It can be seen that under the two load conditions, as the annealing temperature increases, the dislocations can move further away, which can be attributed to the decrease in the critical shear stress. Therefore, the dislocation movement length in the β-Ga2O3 single crystal after annealing can be represented by formula (2):

[0082] l = l0 + l T Formula (2);

[0083] wherein l0 is the dislocation slip length at room temperature caused by nanoindentation, and l T represents the additional dislocation slip length caused by the release of residual stress at elevated temperature. It can be predicted that under the same conditions, including peak load, indenter direction, holding time, and other parameters, l0 remains almost unchanged. During the indentation process, residual stress is generated in the indentation area, and a higher peak load will introduce more residual stress. When this residual stress exceeds the critical stress of the material, it will drive the generation and expansion of dislocations until equilibrium is reached. It is well known that the critical stress decreases with increasing temperature. Therefore, at elevated temperatures, the dislocations are pushed further away from the indentation, explaining that l T monotonically increases with temperature.

[0084] In combination Figure 2Data with a peak load of 30mN and data with a peak load of 100mN (dislocation line obtained with a peak load of 100mN, with other operating parameters the same as in Example 2) can be obtained through l-l0. T l T The dependence on temperature is plotted on Figure 6 middle. Figure 6 For l T The dependence on temperature and its fitting curves are shown. For both loading conditions, the data follow a linear relationship, and the fitting curves are almost parallel to each other, indicating the reliability of the fitting results. Previous studies have shown that l T The expression can be derived as formula (3):

[0085]

[0086] Where B and m are material parameters, k is the Boltzmann constant, T is the temperature, and E is the activation energy of the dislocation. This allows us to obtain the slip distance of indentation-induced dislocations under arbitrary loads and temperatures, thus inferring the influence of dislocations on β-Ga2O3 crystals and providing guidance for subsequent research.

[0087] Furthermore, the dislocation velocity can also be derived from the dislocation line length at elevated temperatures (after annealing). For example, in formula (4):

[0088]

[0089] Where v is the dislocation velocity, τ is the residual stress, and v0 and τ0 are constants. To experimentally determine v, we subjected the samples to rapid thermal annealing at 750, 800, 850, and 900 °C for 60 s after nanoindentation. Thus, we can calculate v using formula (5):

[0090]

[0091] Where t is the holding time during rapid thermal annealing. The data and corresponding fitting curves are as follows: Figure 7 As shown, Figure 7 The relationship between dislocation velocity and temperature and its fitted curve are shown. The data points for both loads are very close to a straight line, and the fitted curves are parallel, indicating the reliability of the results.

[0092] Example 5

[0093] The method is basically the same as that provided in Example 1, except that the sample has a Sn doping concentration of ~4×10⁻⁶. 18 β-Ga2O3(100) crystal plane sample.

[0094] Figure 8 For example, 10mN in Example 5 (Figure 8 the left two etch pits in the upper and lower of 30mN( Figure 8 the middle two etch pits in the upper and lower of 50mN( Figure 8 the right two etch pits in the upper and lower of 50mN( Figure 8 It is shown that using Sn-doped samples, the etch pit morphology characteristic of nanoindentation can also be observed, and the dislocation tailing area is clear and easy to measure.

[0095] Example 6

[0096] The method provided in Example 1 is basically the same, except that the sample is a β-Ga2O3(100) crystal surface sample with Fe doping concentration of about 3×10 17 .

[0097] Figure 9 the left two etch pits in the upper and lower of 30mN( Figure 9 the middle two etch pits in the upper and lower of 50mN( Figure 9 the right two etch pits in the upper and lower of 50mN( Figure 9 the right two etch pits in the upper and lower of 50mN( Figure 9 It is shown that using Fe-doped samples, the nanoindentation etch pit morphology can be observed, but a large number of other etch pit morphologies are observed except for the nanoindentation etch pit, but only the nanoindentation etch pit has obvious dislocation tailing, and the tailing length is easy to measure.

[0098] From the above examples, it can be seen that the present application provides a method of introducing dislocations using nanoindentation and identifying dislocations using wet chemical etching, which has the following advantages: the nanoindentation technology in the present application has strong process compatibility and practical popularization value, and the process is simple and easy to implement. The sample treated by nanoindentation is etched by an alkaline solution, which can clearly etch the introduced

[010] direction dislocation line, which is convenient for subsequent observation and measurement. The present application combines differential interference microscopy to observe and measure the length of the etched dislocation line, which has high measurement accuracy and can accurately obtain the length data of the dislocation line, providing reliable experimental basis for studying dislocation dynamics. The method provided by the present application has simple operation, relatively conventional equipment and low cost, and is easy to popularize and apply, which can effectively study the dynamics behavior of β-Ga2O3(100) crystal surface dislocations, and provide theoretical support and experimental basis for improving the performance of β-Ga2O3 devices.

[0099] Although the above examples have made a detailed description of the present application, it is only a part of the embodiments of the present application, not all the embodiments, and other embodiments can be obtained under the premise of no creativity according to the present embodiments, which all belong to the protection scope of the present application.

Claims

1. A method for obtaining (100) a dislocation line of a crystal plane based on nanoindentation, characterized in that, The method comprises the following steps: (1) aligning a nanoindenter head to a (100) crystal plane of a sample to perform indentation treatment, introducing dislocations in the sample by the indentation treatment, and obtaining a nanoindenter-treated sample; (2) performing etching treatment on the nanoindenter-treated sample to obtain dislocation lines on the (100) crystal plane.

2. The method for obtaining (100) a dislocation line of a crystal plane based on nanoindentation according to claim 1, characterized in that In step (1), the sample is β-Ga2O3 having a (100) crystal plane.

3. The method of claim 1, wherein the nanoindentation-based acquisition (100) of the grain dislocation lines is characterized by, In step (1), the nanoindenter head is a diamond indenter; and the indentation treatment conditions include a loading load of 5-100 mN, a loading rate of 0.1-1 mN / s, a load holding time of 10-60 s, and an unloading rate of 0.1-1 mN / s.

4. The method for obtaining (100) a grain dislocation line based on nanoindentation according to claim 1 or 3, characterized in that In step (1), the dislocations are dislocations slipping along a [010] direction; and in step (2), the dislocation lines are dislocation lines along a [010] direction.

5. The method of claim 1, wherein the nanoindentation-based acquisition (100) of the grain dislocation lines is based on a Berkovich indenter. In step (2), the etching treatment includes wet chemical etching, dry etching, or photoelectrochemical etching.

6. The method for obtaining (100) a grain dislocation line based on nanoindentation according to claim 5, characterized in that The wet chemical etching includes acid solution etching, alkali solution etching, or molten alkali etching; the acid solution etching uses a phosphoric acid solution as the etching reagent, and the etching temperature is ≥ 130 ℃; the alkali solution etching uses a KOH solution as the etching reagent, and the etching temperature is 100-110 ℃; and the molten alkali etching uses molten KOH and / or molten NaOH as the etching reagent, and the etching temperature is ≥ 200 ℃.

7. The method of claim 6, wherein the nanoindentation-based acquisition (100) of the grain dislocation lines is characterized by, The mass content of KOH in the KOH solution is 20-40%; and the alkali solution etching time is 30-180 min.

8. The method of claim 1, wherein the nanoindentation-based acquisition (100) of the grain dislocation lines is based on a Berkovich indenter. After obtaining the nanoindenter-treated sample, before performing the etching treatment, the method further comprises performing annealing treatment on the nanoindenter-treated sample, wherein the annealing treatment temperature is room temperature-1200 ℃, and the annealing holding time is 30-60 s. In step (2), after obtaining the dislocation lines, the method further comprises recording and measuring information of the dislocation lines by using a differential interference microscope, wherein the information includes the length of the dislocation lines.

9. A method for studying the dislocation dynamics of a crystal plane based on nanoindentation (100), characterized in that, The (100) crystal plane dislocation lines are obtained by the method according to any one of claims 1-8; and (100) crystal plane dislocation kinetics is studied according to the (100) crystal plane dislocation lines.

10. The method of investigating (100) the dynamics of dislocations in a crystal plane based on nanoindentation according to claim 9, characterized in that, The (100) crystal plane dislocation kinetics includes the corresponding relationship between the length of the (100) crystal plane dislocation lines and the peak load of the indentation treatment, the corresponding relationship between the length of the extra dislocations and the annealing temperature of the annealing treatment after the indentation treatment, and the corresponding relationship between the dislocation velocity and the annealing temperature of the annealing treatment after the indentation treatment.

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