Raman scattering method for measuring GaN thermal expansion coefficient

A thermal expansion coefficient and scatterometer technology, which is applied in the direction of material thermal expansion coefficient, Raman scattering, material excitation analysis, etc., can solve the problems of unfavorable influence of measurement results, difficult to measure accurately, and small thermal expansion coefficient of GaN, so as to avoid formula derivation and Mathematical calculations, clear physical meaning, simple formula effect

Inactive Publication Date: 2016-05-25
XI'AN PETROLEUM UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0012] There are many disadvantages in using a thermal dilatometer to test the thermal expansion coefficient of GaN epitaxial film: 1) GaN material has high hardness and high brittleness, making it difficult to make strips / standard samples; 2) GaN has a small thermal expansion coefficient, so during the heating process, The size increase effect caused by volume expansion is small, and it is difficult to measure accurately; 3) Most importantly, GaN materials are mostly grown by heteroepitaxial growth, and the thickness of the thin film material is generally small (a sapphire substrate with a thickness of 430 microns, Plus buffer layer / nucleation layer, etc., the thickness of epitaxially grown GaN is generally about 600 microns), and this layered structure will have an adverse effect on the measurement results

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  • Raman scattering method for measuring GaN thermal expansion coefficient
  • Raman scattering method for measuring GaN thermal expansion coefficient
  • Raman scattering method for measuring GaN thermal expansion coefficient

Examples

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Effect test

Embodiment 1

[0040] A Raman scattering method for GaN thermal expansion coefficient measurement comprises the following steps:

[0041] Step 1, sampling and cleaning the GaN epitaxial film sample.

[0042] Use a diamond glass knife to slice the grown GaN film sample with a diameter of 2 inches to make a sample with a size of about 1cm×1cm. The GaN epitaxial layer film is cleaned on the surface, and the a-plane GaN epitaxial layer The film is placed in a vacuum of 5.0×10 -3 In the mbar CVD furnace chamber, nitrogen gas with a flow rate of 60-100 liters per minute is introduced at room temperature to remove scratches and surface attachments on the surface of the film;

[0043] Step 2, conduct variable temperature Raman test on the GaN sample;

[0044] 1) Place the cleaned GaN epitaxial film sample on the Raman scattering test bench, adjust the Raman scattering instrument, connect the variable temperature platform and the liquid nitrogen tank, and set the test temperature range and step len...

Embodiment 2

[0061] A Raman scattering method for GaN thermal expansion coefficient measurement comprises the following steps:

[0062] Step 1, sampling and cleaning the GaN epitaxial film sample;

[0063] Use a diamond glass knife to slice the grown GaN film sample with a diameter of 2 inches to make a sample with a size of about 1cm×1cm. The GaN epitaxial layer film is cleaned on the surface, and the a-plane GaN epitaxial layer The film is placed in a vacuum of 5.0×10 -3 In the mbar CVD furnace chamber, nitrogen gas with a flow rate of 60-100 liters per minute is introduced at room temperature to remove scratches and surface attachments on the surface of the film;

[0064] Step 2, conduct variable temperature Raman test on the GaN sample;

[0065] 1) Place the cleaned GaN epitaxial film sample on the Raman scattering test bench, adjust the Raman scattering instrument, connect the variable temperature platform and the liquid nitrogen tank, and set the test temperature range and step len...

Embodiment 3

[0082] A Raman scattering method for GaN thermal expansion coefficient measurement comprises the following steps:

[0083] Step 1, sampling and cleaning the GaN epitaxial film sample;

[0084] Use a diamond glass knife to slice the grown GaN film sample with a diameter of 2 inches to make a sample with a size of about 1cm×1cm. The GaN epitaxial layer film is cleaned on the surface, and the a-plane GaN epitaxial layer The film is placed in a vacuum of 5.0×10 -3 In the mbar CVD furnace chamber, nitrogen gas with a flow rate of 60-100 liters per minute is introduced at room temperature to remove scratches and surface attachments on the surface of the film;

[0085] Step 2, performing temperature-varying Raman tests on the GaN epitaxial layer thin film sample;

[0086] 1) Place the cleaned GaN epitaxial film sample on the Raman scattering test bench, adjust the Raman scattering instrument, connect the variable temperature platform and the liquid nitrogen tank, and set the test t...

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Abstract

A Raman scattering method for measuring a GaN thermal expansion coefficient includes the following steps that 1, a sample is scribed, sampled and cleaned; 2, variable-temperature Raman testing is performed on the sample; 3, linear fitting is performed on a testing result, and the linear fitting slope and intercept are extracted. According to the extracting result, the thermal expansion behavior of a solid material is tested and represented in combination with the physical meaning of Gruneisen parameters. The variable-temperature Raman scattering technology is adopted, Raman scattering is utilized for obtaining the relation between Raman phonon frequency shift and temperature, nondestructive testing and representing can be accurately performed on thermal expansion behaviors of epitaxial layer film two-element and multi-element alloy systems of GaN, AlN, InN and other III group nitrides, and therefore it is avoided that in a common representation method, the sample is damaged, and formula derivation and mathematical calculation are complex; because no strict requirements for the shape and size of the sample exist, the thermal expansion behaviors of all kinds of semiconductor materials can be conveniently tested, and the method is simple, easy to implement and small in error.

Description

technical field [0001] The invention belongs to the technical field of testing methods for thermal expansion behavior of solid materials, and in particular relates to a Raman scattering method for measuring the thermal expansion coefficient of GaN, which is used for the measurement and characterization of the thermal expansion coefficient of GaN thin film materials. The relationship between frequency shift and temperature is analyzed, combined with the expansion law of solid materials, the relationship between the thermal expansion behavior of materials and the variable temperature Raman scattering frequency shift is processed, so as to obtain the relevant information about the thermal expansion behavior of GaN thin film materials. Background technique [0002] Group III nitride binary and multi-element alloy optoelectronic materials are ideal candidates for realizing solid-state lighting (Solid-State Lighting, SSL), and also for realizing semiconductor light-emitting diodes ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N21/65G01N25/16
CPCG01N21/65G01N25/16
Inventor 王党会许天旱宋海洋王磊
Owner XI'AN PETROLEUM UNIVERSITY
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