阅读说明：本技术 基于x射线的AlGaN层Al组分测定方法 (Method for measuring Al component of AlGaN layer based on x-ray ) 是由 朱明兰 左万胜 胡新星 仇成功 赵海明 钮应喜 袁松 王丽多 于 2021-08-12 设计创作，主要内容包括：本发明公开一种基于x射线的AlGaN层Al组分测定方法,包括如下步骤：S1、对GaN的(114)晶面进行XRD的2θ-ω扫描,计算AlGaN(114)晶面的面间距测量值d-(测)；S2、对AlGaN层中的Al组分x进行赋值,计算不同x值下AlGaN(114)晶面的面间距计算值d-(计)；S3、输出与面间距测量值d-(测)偏差最小的面间距计算值d-(计)及其对应的x值。不需要利用RSM图测定驰豫度的情况下,通过扫描受双轴应力影响较小的(114)晶面的2θ曲线,就能较为准确的测定AlGaN层中Al组分,能够减少测试时间,同时提高测试效率。(The invention discloses an AlGaN layer Al component determination method based on x-rays, which comprises the following steps: s1, 2 theta-omega scanning of XRD was performed on the GaN (114) crystal plane, and the measured value d of the interplanar spacing of the AlGaN (114) crystal plane was calculated Measuring (ii) a S2, assigning an Al component x in the AlGaN layer, and calculating the calculated surface distance d of the AlGaN (114) crystal surface under different x values Meter (ii) a S3, outputting the measured value d of the distance between the surface and the plane Measuring Calculated value d of minimum surface spacing Meter And its corresponding x value. Under the condition of not using an RSM (stress-relief modulation) diagram to determine the relaxation degree, the Al component in the AlGaN layer can be determined more accurately by scanning the 2 theta curve of the (114) crystal face which is less affected by biaxial stress, the testing time can be shortened, and the testing efficiency can be improved.)

1. An AlGaN layer Al component determination method based on x-rays is characterized by specifically comprising the following steps of:

s1, 2 theta-omega scanning of XRD was performed on the GaN (114) crystal plane, and the measured value d of the interplanar spacing of the AlGaN (114) crystal plane was calculated_Measuring；

S2, assigning an Al component x in the AlGaN layer, and calculating the calculated surface distance d of the AlGaN (114) crystal surface under different x values_Meter；

S3, outputting the measured value d of the distance between the surface and the plane_MeasuringCalculated value d of minimum surface spacing_MeterAnd its corresponding x value.

2. The x-ray based method for determining the Al composition of an AlGaN layer according to claim 1, wherein the inter-plane distance of the AlGaN (114) lattice plane is measuredValue d_MeasuringThe acquisition method specifically comprises the following steps:

s11, reading the Bragg angle of the AlGaN (114) crystal plane from the 2 theta-omega scanning curve;

s12, substituting the Bragg angle into a Bragg formula to obtain a measured value d of the surface distance of the AlGaN (114) crystal surface_Measuring。

3. The method for determining Al composition of an x-ray based AlGaN layer according to claim 1, wherein the calculated value d of the inter-plane distance in the plane of AlGaN (114) is calculated_MeterThe method comprises the following specific steps:

s21, calculating lattice constants a and c of AlGaN corresponding to different x values;

s22, calculating a calculated value d of the surface distance of AlGaN (114) crystal plane based on lattice constants a and c of AlGaN_Meter。

4. The method of claim 3, wherein the lattice constants a and c of AlGaN are calculated as follows:

a＝xa^AlN+(1-x)a^GaN

c＝xc^AlN+(1-x)c^GaN

wherein x represents an Al composition in the AlGaN layer;

a^AlN、c^AlNis the lattice constant of AlN, respectivelyAnd

a^GaN、c^GaNis the lattice constant of GaN, respectivelyAnd

5. the method for measuring Al composition of an x-ray based AlGaN layer according to claim 3, wherein the calculated value d of the interplanar spacing in the AlGaN (114) lattice plane is_MeterThe calculation formula of (a) is specifically as follows:

wherein a and c are lattice constants of AlGaN; h. k and l are Miller indices of AlGaN (114) crystal plane.

Technical Field

The invention belongs to the technical field of semiconductors, and particularly relates to an x-ray-based AlGaN layer Al component determination method.

Background

Reciprocal Space (RSM) scanning can reflect the information of the crystal face spacing, the relaxation degree, the inclination and the like of the material, accurately reflects the fine structure change in the sample, and is an ideal Al component testing method. However, this scanning method is time-consuming and requires a plurality of omega-2 theta scans.

The existing AlGaN layer Al component measuring method determines the average relaxation degree through RSM scanning data of a (104) crystal face RSM scanning and a (002) crystal face omega-2 theta scanning of a GaN material, and improves the accuracy of Al component testing of the (002) crystal face omega-2 theta scanning data. The existing Al component determination method has the problems of complicated measurement steps and long scanning time.

Disclosure of Invention

The invention provides an AlGaN layer Al component determination method based on x-rays, aiming at reducing scanning time and improving test efficiency.

The invention is realized in such a way that an AlGaN layer Al component determination method based on x-rays specifically comprises the following steps:

s1, 2 theta-omega scanning of XRD was performed on the GaN (114) crystal plane, and the measured value d of the interplanar spacing of the AlGaN (114) crystal plane was calculated_Measuring；

S2, assigning an Al component x in the AlGaN layer, and calculating the calculated surface distance d of the AlGaN (114) crystal surface under different x values_Meter；

S3, outputting the measured value d of the distance between the surface and the plane_MeasuringCalculated value d of minimum surface spacing_MeterAnd its corresponding x value.

Further, a measured value d of the plane-to-plane spacing of AlGaN (114) crystal plane_MeasuringThe acquisition method specifically comprises the following steps:

s11, reading the Bragg angle of the AlGaN (114) crystal plane from the 2 theta-omega scanning curve;

s12, substituting the Bragg angle into the Bragg formula to obtain the AlGaN (114) crystal faceMeasured value of interplanar spacing d_Measuring。

Further, a calculated value d of the surface-to-surface distance of AlGaN (114) crystal plane_MeterThe method comprises the following specific steps:

s21, calculating lattice constants a and c of AlGaN corresponding to different x values;

s22, calculating a calculated value d of the surface distance of AlGaN (114) crystal plane based on lattice constants a and c of AlGaN_Meter。

Further, the calculation formulas of lattice constants a and c of AlGaN are specifically as follows:

a＝xa^AlN+(1-x)a^GaN

c＝xc^AlN+(1-x)c^GaN

wherein x represents an Al composition in the AlGaN layer;

a^AlN、c^AlNis the lattice constant of AlN, respectivelyAnd

a^GaN、c^GaNis the lattice constant of GaN, respectivelyAnd

further, a calculated value d of the surface-to-surface distance of AlGaN (114) crystal plane_MeterThe calculation formula of (a) is specifically as follows:

wherein a and c are lattice constants of AlGaN; h. k and l are Miller indices of AlGaN (114) crystal plane.

According to the method for measuring the Al component of the AlGaN layer, provided by the invention, under the condition that the relaxation degree is not required to be measured by using an RSM (stress-saturation-modulation) diagram, the Al component in the AlGaN layer can be measured more accurately by scanning the 2 theta curve of the (114) crystal face which is less influenced by biaxial stress, the test time can be reduced, and the test efficiency can be improved.

Drawings

FIG. 1 is a schematic structural diagram of a sample provided in an embodiment of the present invention;

FIG. 2 is a flowchart of a method for determining Al composition of an AlGaN layer based on x-rays according to an embodiment of the present invention;

fig. 3 is a 2 θ - ω scan graph of the AlGaN (114) crystal plane according to an embodiment of the present invention.

Detailed Description

The following detailed description of the embodiments of the present invention will be given in order to provide those skilled in the art with a more complete, accurate and thorough understanding of the inventive concept and technical solutions of the present invention.

Selecting a diffraction crystal face with high diffraction intensity and small plane spacing influenced by biaxial stress from a crystal face group of a GaN material, and performing 2 theta-omega scanning on the crystal face to determine the Al component of the AlGaN layer, wherein the test flow of the determination method is shown in figure 2, and the test method comprises the following steps:

s1, 2 theta-omega scanning of XRD is carried out on the asymmetric plane (114) crystal plane of the GaN material, and the measured value d of the plane spacing of the AlGaN (114) crystal plane is calculated_MeasuringThe calculation method is as follows:

s11, reading the Bragg angle of the AlGaN (114) crystal plane from the 2 theta-omega scanning curve;

s12, substituting the Bragg angle theta into the Bragg formula 2d_Measuringsin θ ═ λ, where λ is the wavelength of the x-rays,obtaining a measured value d of the surface distance of the AlGaN (114) crystal surface_Measuring。

S2, assigning an Al component x in the AlGaN layer, and calculating the calculated surface distance d of the AlGaN (114) crystal surface under different x values_Meter；

S21, calculating lattice constants a and c of AlGaN corresponding to different x values, wherein the calculation method comprises the following steps:

a＝xa^AlN+(1-x)a^GaN

c＝xc^AlN+(1-x)c^GaN

wherein x represents an Al composition in the AlGaN layer; a is^AlN、c^AlNIs the lattice constant of AlN, respectivelyAnda^GaN、c^GaNis the lattice constant of GaN, respectivelyAnd

s22, calculating a calculated value d of the surface distance of AlGaN (114) crystal plane based on lattice constants a and c of AlGaN_MeterThe calculation formula is as follows:

wherein a and c are lattice constants of AlGaN; h. k and l are Miller indices of AlGaN (114) crystal plane.

Fig. 1 shows a structural diagram of an exemplary sample, which includes a single crystal substrate 1, an AlN transition layer 2, an AlGaN transition layer i 3, an AlGaN transition layer ii 4, an AlGaN transition layer iii 5, and a GaN high-resistance layer 6 grown on the AlGaN transition layer iii 5, which are sequentially grown on the single crystal substrate 1, wherein the single crystal substrate 1 is a 6-inch Si single crystal wafer, and has crystal planes (111) ± 0.2 degrees, and a positioning edge crystal plane (110).

The equipment used by the invention is a JV-Delta-X type high-resolution X-ray diffractometer produced by Bruker UK Limited. The high-resolution diffractometer is provided with a Cu target x-ray source, a detector and a carrying platform. The incident direction of the x-ray is parallel to the (110) crystal plane of the Si single crystal substrate. The rotation range of the X-ray light source and the detector is-5-95 degrees. The microscope carrier is provided with 5 rotating shafts which are respectively a Phi shaft, a Chi shaft, an X shaft, a Y shaft and a Z shaft. The ω -axis and the 2 θ -axis are perpendicular to the plane formed by the incident x-ray beam and the x-ray detector. The method for measuring the Al component of the AlGaN layer specifically comprises the following steps:

for the GaN (114) crystal plane to face light, the specific process comprises the following steps: and rotating the omega and 2 theta axes to the GaN glancing angle position, rotating the phi axis by 30 degrees, and optimizing the omega, 2 theta, phi and chi angles to ensure that the diffraction intensity is strongest. Then 2 theta-omega scanning is carried out on the crystal plane of the GaN high-resistance layer asymmetric surface (114), and the 2 theta-omega scanning parameters are set as follows: scanning step 0.01 °, scanning range: 99-106 °, count time: 0.3sec, and a total scan duration of 5min, the 2 θ - ω curve shown in fig. 3 was obtained.

In the step, the (114) crystal plane obtained from the GaN material is used as a measurement crystal plane, compared with the (205) crystal plane obtained by scanning the GaN material, the scanning angle can be reduced by 7 degrees, in addition, the (205) crystal plane is a high-index crystal plane, the omega angle is 105 degrees, and the measurement range of the common equipment is exceeded.

Reading Bragg angles of the AlGaN transition layer I, the AlGaN transition layer II and the AlGaN transition layer III from a 2 theta-omega curve, and respectively using theta₁、θ₂And theta₃。

The measured Bragg angle theta₁、θ₂And theta₃Respectively substituting into Bragg formula to obtain the surface spacing d of (114) crystal face₁、d₂And d₃The bragg formula is specifically as follows:

d＝λ/2sinθ

wherein the wavelength λ of the x-rays is

Assigning an Al component x in the AlGaN transition layer I by a set step length, wherein x is₁、x₂、…、x_nCalculating the calculated value d of the surface distance of AlGaN (114) crystal planes under different x values_MeterThe calculation process is as follows:

calculating lattice constants a and c of AlGaN corresponding to different x values, wherein the calculation method comprises the following steps:

a＝xa^AlN+(1-x)a^GaN

c＝xc^AlN+(1-x)c^GaN

wherein x represents an Al composition in the AlGaN layer; a is^AlN、c^AlNIs the lattice constant of AlN, respectivelyAnda^GaN、c^GaNis the lattice constant of GaN, respectivelyAnd

calculation of the surface spacing value d of AlGaN (114) lattice plane based on the lattice constants a and c of AlGaN_MeterThe calculation formula is as follows:

wherein a and c are lattice constants of AlGaN; h. k and l are Miller indices of AlGaN (114) crystal plane.

Finally, the measured value d of the distance between the output and the surface is output_MeasuringCalculated value d of minimum surface spacing_MeterAnd its corresponding x value.

The method can measure the x components in the AlGaN transition layer II and the AlGaN transition layer III, so that the method for measuring the Al component of the AlGaN layer provided by the invention is suitable for measuring the Al components of a single AlGaN layer and a multi AlGaN layer.

According to the method for measuring the Al component of the AlGaN layer, provided by the invention, under the condition that the relaxation degree is not required to be measured by using an RSM (stress-saturation-modulation) diagram, the Al component in the AlGaN layer can be measured more accurately by scanning the 2 theta curve of the (114) crystal face which is less influenced by biaxial stress, the test time can be reduced, and the test efficiency can be improved.

To better illustrate the test effect of the test method, the test method described in the background art (i.e., the existing Al component test method) was used for testing, and the test results of the samples are referred to table 1 below;

table 1 comparative table of test results

As can be seen from Table 1, the Al component test method provided by the invention has basically the same test result as the existing test method, but the Al component test method provided by the invention has the advantages of short actual measurement time and high test efficiency.

The invention has been described above with reference to the accompanying drawings, it is obvious that the invention is not limited to the specific implementation in the above-described manner, and it is within the scope of the invention to apply the inventive concept and solution to other applications without substantial modification.