A Testing Method and Application of Carrier Concentration and Mobility of PN Junction Materials

Abstract

The present invention relates to the technical field of semiconductors, and discloses a method and application for testing the carrier concentration and mobility of a PN junction material. The testing method includes: performing a Hall test on an N-type substrate to obtain the carrier concentration n and mobility μ of the N-type substrate n ; doping P-type ions on the N-type substrate to form a P-on-N structure sample, performing a Hall test on the sample, and measuring the Hall coefficient R h , resistivity ρ; etching the P-on-N structure sample with an etching solution to form an inclined mesa, measuring the etching depth h; determining the junction depth using the IV curve to obtain the thickness d of the P layer p and the thickness d of the N-type layer n ; substituting into the calculation formula to obtain the P-type carrier concentration p and the P-type carrier mobility μ p . The PN junction material testing method of the present invention can effectively test the bipolar carrier concentration and mobility of electrons and holes. The testing method is simple, with small errors, and can effectively solve problems such as inaccurate carrier measurement and inability to measure the P-type concentration, and cumbersome testing processes

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductors, and particularly relates to a method for testing the carrier concentration and mobility of a PN junction material and its application. Background Art

[0002] A PN junction is a material in which holes and electrons participate in conduction together, and has complex electrical transport characteristics. Especially after injection and junction formation, the electrical transport behavior cannot be tested and characterized by a single method. Therefore, a reasonable and scientific method is needed to test and build a simulation model for its PN junction device.

[0003] In the prior art, the Hall effect is commonly used to characterize the transport characteristics of a PN junction, and the carrier type is determined and the concentration is calculated according to the magnitude and sign of the Hall coefficient. However, a PN junction containing bipolar carriers (such as mercury cadmium telluride after junction formation) has both holes and electrons as carriers, and it is impossible to simply judge its carrier type and concentration through the Hall effect. The effective mass of holes in the mercury cadmium telluride material is more than 30 times that of electrons, and the mobility is much smaller than that of electrons, with a difference of up to two orders of magnitude. Therefore, a good P-type mercury cadmium telluride is often misjudged as a weak N-type in Hall tests and cannot be processed into wafers, resulting in huge waste.

[0004] The prior art also commonly uses the layer stripping Hall method to test the bipolar carrier concentration of a PN junction containing bipolar carriers. The entire sample is completely immersed in the etching solution, the etching thickness is measured using a Fourier transform infrared spectrometer, and the carrier test is carried out using a Hall test system. Usually, etching needs to be repeated more than 6 times, and finally the carrier concentration of the material peeled off each time is obtained by fitting. The entire process of the layer stripping Hall method is too cumbersome, and it often takes half a day for one device, extremely wasting manpower. At the same time, the combination of layer-by-layer etching and Fourier testing has limited accuracy, with an error greater than 0.3 μm, and it is impossible to obtain the accurate thickness of the P-type layer, resulting in large errors in the calculation of carrier concentration and mobility.

[0005] Therefore, in order to address the problems of cumbersome testing methods and inaccurate results in the prior art, there is an urgent need for a method for testing the carrier concentration and mobility of a PN junction material that is simple and has small errors. Summary of the Invention

[0006] In order to solve the problems of cumbersome testing methods and inaccurate testing results in the prior art, the present invention provides a method for testing the carrier concentration and mobility of a PN junction material and its application. The method for testing the carrier concentration and mobility of a PN junction material of the present invention can obtain the bipolar carrier concentration and mobility of electrons and holes, and the testing method is simple with small errors, which can effectively solve the problems in the prior art that the carrier measurement is inaccurate and the P-type concentration cannot be measured, as well as solve the problems of cumbersome testing process, decreased yield, and waste of manpower and material resources.

[0007] One object of the present invention is to provide a method for testing the carrier concentration and mobility of a PN junction material, including:

[0008] S1. Perform Hall measurement on the N-type substrate to obtain the carrier concentration n and mobility μ of the N-type substrate n ;

[0009] S2. Dope P-type ions on the N-type substrate by ion implantation process to form a P-on-N structure sample, and perform Hall measurement on the P-on-N structure sample to measure the Hall coefficient R h , resistivity ρ;

[0010] S3. Corrode the P-on-N structure sample obtained in step S2 with a corrosion solution to form an inclined plane, and measure the corrosion depth h;

[0011] S4. Then use the IV curve to determine the junction depth to obtain the P-layer thickness d p of the P-on-N structure and the N-type layer thickness d n ;

[0012] The P-type carrier concentration p and mobility μ of the PN junction material p The calculation formulas are shown in the following formulas (1) and (2) respectively:

[0013]

[0014] Wherein, d in the above formulas (1) and (2) p is the P-layer thickness, d n is the N-type layer thickness, q is the electronic charge, n is the carrier concentration of the N-type substrate, μ n is the mobility of the N-type substrate, R h is the Hall coefficient of the P-on-N structure sample, and ρ is the resistivity.

[0015] The testing method of the present invention uses the IV curve to determine the junction depth. Compared with the capacitance-voltage method, by leading out the top electrode of the passivation layer and the bottom electrode of the mercury cadmium telluride, sweeping the voltage to measure the capacitance, and measuring the carrier concentration, mobility and junction depth through fitting calculation. The test result of the capacitance-voltage method is affected by the bulk electron concentration of the passivation layer and cannot directly reflect the carrier concentration of the PN junction, and the electrode lead-out process is relatively difficult. The PN junction depth position is confirmed by the IV curve, and then the specific junction depth is measured by a step profiler.

[0016] The mobility spectrum method directly measures the Hall effect of the sample, and can measure the carrier concentration of the multi-carrier system by combining fitting, but there are often peak spectra unrelated to the PN junction in the calculation process, that is, the carrier concentration without actual physical meaning, and the junction depth data cannot be obtained.

[0017] The layer-by-layer Hall measurement method uses layer-by-layer etching, layer-by-layer measurement, and layer-by-layer fitting to obtain the carrier concentration mobility and the corresponding junction depth at different depths of the sample. However, the process is extremely cumbersome, and the calculation accuracy is greatly affected by etching and Fourier transform infrared spectrometer testing. The accuracy of the obtained data is low, especially the junction depth position cannot be accurately confirmed.

[0018] In contrast, the present invention uses the IV curve to determine the junction depth, which can calculate the junction depth more accurately. Given the known thickness of the N-type layer, the carrier concentration and mobility of the P-on-N mixed carriers, an inclined plane with a depth of 0.01 - 10 μm is formed by etching, and IV test electrodes are formed on the PN junction device by micro-nano processing. The junction depth is confirmed based on the change of the IV curve from the resistance characteristic to the diode characteristic. Combining the above junction depth, N-type layer, and P-on-N mixed carrier concentration and mobility, the carrier concentration and mobility of the P-type layer formed by injection can be calculated using a formula. To improve the test accuracy, the steps of the inclined plane can be seen, and the inclined plane can also be regarded as an inclined table.

[0019] According to a preferred embodiment of the present invention, the N-type substrate is any one of mercury cadmium telluride, vanadium oxide, indium gallium arsenide, and indium antimonide; preferably mercury cadmium telluride;

[0020] And / or, the P-type ion is any one of As ions, Cu ions, Ag ions, and Au ions; preferably As ions;

[0021] Preferably, the thickness of the N-type substrate is 1 - 100 μm; preferably 1 - 50 μm; more preferably 2 - 10 μm; further preferably 3 - 9 μm; the length is 0.1 - 100 mm, preferably 10 - 50 mm; the width is 0.1 - 100 mm, preferably 10 - 50 mm;

[0022] Preferably, the energy of the As ion implantation is 60 - 500 KeV, preferably 100 - 180 KeV; the dose is 10 11 ~10 16 / cm 2 .

[0023] According to a preferred embodiment of the present invention, the step of forming the inclined plane (or inclined table) in step S3 includes applying photoresist on the edge of the P-on-N structure sample, immersing it in a 0.1 - 30 wt% bromo-methanol etching solution, immersing it downward by 0.01 - 5 mm every 0.1 - 10 s until the inclined plane is formed, and then removing the etching solution and photoresist on the surface. It is preferred to use methanol and / or acetone to clean and remove the etching solution and photoresist on the surface of the sample.

[0024] According to a preferred embodiment of the present invention, before measuring the IV curve in step S4, the P-on-N structure sample also undergoes a patterning process.

[0025] According to a preferred embodiment of the present invention, in step S1, the Hall test is carried out in a Hall test system, and the Hall coefficient R of the material is measured using the Van der Pauw method h , resistivity ρ; preferably, the Hall test is carried out under the action of a first magnetic field perpendicular to the N-type substrate, a first current passes through the N-type substrate, and the first Hall voltage V is measured y1 , and the Hall test system calculates the N-type carrier concentration n and mobility μ n ; more preferably, the magnetic field strength of the first magnetic field is 0-10T, and the current intensity I of the first current x1 is 0-10 mA.

[0026] According to a preferred embodiment of the present invention, in step S2, the indium pressing lead electrode of the P-on-N structure sample is connected to the Hall test system for Hall test; preferably, the Hall test is carried out under the action of a second magnetic field perpendicular to the P-on-N structure sample, a second current passes through the P-on-N structure sample, and the second Hall voltage V is measured y2 , and the Hall test system calculates the Hall coefficient R of the P-on-N structure sample h and resistivity ρ; more preferably, the magnetic field strength of the second magnetic field is 0-10T, and the current intensity I of the second current x2 is 0-10 mA.

[0027] According to a preferred embodiment of the present invention, in step S4, the P-on-N structure sample after being etched in step S3, after coating with glue, photolithography and development, and then after etching treatment, the IV curve corresponding to the P-on-N structure sample is measured using a semiconductor parameter tester; preferably, the etching depth is 0.01-10 μm; and / or, the junction depth corresponding to the IV curve changes from a resistance characteristic to a diode characteristic.

[0028] According to a preferred embodiment of the present invention, the measuring instrument for the step measurement is a profiler;

[0029] and / or, the instrument for coating with glue is a spin coater;

[0030] and / or, the instrument for photolithography and development is a photolithography machine;

[0031] and / or, the etching is ICP etching;

[0032] and / or, the semiconductor parameter tester is a Keithley 4200 semiconductor parameter tester.

[0033] The second object of the present invention is to provide the application of the test method of the PN junction material in the field of infrared detectors.

[0034] The beneficial effects of the present invention are as follows: By using the present invention to measure and fit the material parameters of PN junction devices, the measurement accuracy of the junction depth reaches 0.05 μm, the difficulty in testing P-type carriers is solved, and relatively accurate carrier concentration mobility can be obtained.

[0035] It has a guiding role in the infrared detector process with low noise, low lateral diffusion, and low leakage, can improve the detector design and development ability, optimize the carrier concentration and mobility of the material, reduce the dark current of the device, and improve the performance of the focal plane assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic flow chart of the PN junction material testing method of this application. DETAILED DESCRIPTION OF THE INVENTION

[0037] The present invention will be further described below in conjunction with specific embodiments, but it does not constitute any limitation to the present invention.

[0038] In the following embodiments, the N-type substrate is a mercury cadmium telluride material; the size of the N-type substrate is 20*20 mm, and the thickness is 8 μm;

[0039] The P-type ion is an As ion;

[0040] The measuring instrument for step measurement is a step meter;

[0041] The instrument for coating glue is a glue coater;

[0042] The instrument for photolithography and development is a photolithography machine;

[0043] The etching is ICP etching;

[0044] The semiconductor parameter tester is a Keithley 4200 semiconductor parameter tester.

[0045] Figure 1 In, junction formation and metallization are general terms in the industry. Junction formation in this patent can be understood as forming a PN junction by ion implantation, and metallization is growing a metal film layer to lead out test electrodes.

[0046]

Embodiment 1

[0047] As Figure 1 shown, the test method for the carrier concentration and mobility of the PN junction material of the present invention includes the following steps:

[0048] S1. Select a mercury cadmium telluride sample as the N-type substrate, use indium pressing to lead out the Hall test electrode and connect it to the Hall test system, add liquid nitrogen to cool down to 77 K, the first magnetic field is ±1 T, and pass a transverse first current I x = 1 mA, and measure the longitudinal first Hall voltage V y1 , and the Hall test system is based on the size, thickness of the N-type substrate and the first Hall voltage Vy1 , the carrier concentration n of the N-type substrate can be directly measured as n = 9×10 14 / cm 3 and the mobility μ n = 10500 cm 2 / V·s;

[0049] S2. Inject As ions with an energy of 150 keV into the HgCdTe sample to form a P-on-N structure sample. The P-on-N structure sample uses indium pressing to lead out the Hall test electrodes, connect to the Hall test system, add liquid nitrogen to cool down to 77 K, the second magnetic field is ±1 T, and pass a transverse second current I x = 1 mA, measure the longitudinal second Hall voltage V y2 , and the Hall test system can directly measure the Hall coefficient R of the P-on-N structure sample according to the size, thickness of the P-on-N structure sample and the second Hall voltage V y2 = 3.035 cm h / C and the resistivity ρ = 0.35 Ω·cm. 3 / C and resistivity ρ = 0.35 Ω·cm.

[0050] S3. Coat photoresist on the edge of the HgCdTe sample for protection, immerse it vertically (the HgCdTe sample is perpendicular to the solution liquid surface) in a 0.5% bromine methanol etching solution, immerse 1 mm downward every 5 s, for a total of 100 s of etching, and then put it into methanol solution for 3 min and acetone solution for 5 min to remove bromine methanol and photoresist, and use a step profiler to measure the edge step to determine the etching depth h.

[0051] S4. Pattern the HgCdTe sample by photolithography and etching means, place the PN junctions with different depths in a low-temperature environment to measure the IV curve to determine the junction depth, and obtain the P-layer thickness d p and the N-type layer thickness d n . The junction depth is determined by measuring the IV curve of the inclined mesa. The inclined mesa is formed by etching, half of it has the characteristics of a PN junction, and the other part is the N-type layer. The critical thickness at which the IV curve can be detected is the junction depth.

[0052] Place the P-on-N sample on a spin coater with a rotation speed of 6000 r / min. After lithography exposure and development, use ICP etching to form a PN junction device with an etching depth of 0.5 μm. Use a Keithley 4200 semiconductor parameter tester to measure the IV curve. The corrosion depth h corresponding to the change of the IV curve from the resistance characteristic to the diode characteristic is the junction depth, and the measurement accuracy can reach 0.05 μm, that is, the P-type layer thickness d p = 1.35 μm, and the total thickness of 8 μm minus d p is the N-type layer thickness d n = 6.65 μm.

[0053] The d in the following formulas (1) and (2)p is the thickness of the P layer, d n is the thickness of the N-type layer, q is the electron charge, n is the carrier concentration of the N-type substrate, μ n is the mobility of the N-type substrate, R h is the Hall coefficient of the P-on-N structure sample, and ρ is the resistivity.

[0054] According to formula (1) and formula (2), the n and μ are measured. n , R h d p d n , ρ are fitted, the P-type carrier concentration p and mobility μ of the PN junction material p Calculation formula.

[0055]

[0056] The calculation shows that the P-type carrier concentration p = 2.3 × 10 18 / cm 3 , mobility μ p =650cm 2 / V·s.

[0057] The thickness is measured by calculating the infrared transmission spectrum and combining the above formula (1) and formula (2) to obtain the thickness. However, the surface of mercury cadmium telluride is rough and the measurement error of the transmission spectrum is 0.05 microns.

[0058] [Example 2]

[0059] The method for testing carrier concentration and mobility of PN junction materials of the present invention comprises the following steps:

[0060] S1. Select the HgCdTe sample as the N-type substrate, use the indium pressure to lead out the Hall test electrode to connect the Hall test system, add liquid nitrogen to cool down to 77K, the first magnetic field is ±1T, and the first transverse current I is passed. x =1mA, measure the first longitudinal Hall voltage V y1 The Hall test system is based on the size, thickness and first Hall voltage V of the N-type substrate. y1 , the carrier concentration of N-type substrate can be directly measured as n = 9 × 10 14 / cm 3 and mobility μ n =10500cm 2 / V·s;

[0061] S2, As ions with energy of 300KeV are implanted into the HgCdTe sample to form a P-on-N structure sample. The P-on-N structure sample uses pressed indium to lead out the Hall test electrode, connects to the Hall test system, adds liquid nitrogen to cool down to 77K, the second magnetic field is ±1T, and the transverse second current I is passedx = 1 mA, measure the longitudinal second Hall voltage V y2 , the Hall test system can directly measure the Hall coefficient R of the P-on-N structure sample according to the size, thickness of the P-on-N structure sample and the second Hall voltage V y2 of the P-on-N structure sample h = 2.035 cm 3 / C and resistivity ρ = 0.5 Ω·cm.

[0062] S3. Apply photoresist protection to the edge of the mercury cadmium telluride sample, immerse it vertically in 0.5% bromine methanol etching solution, immerse it 1 mm downward every 5 s, and etch for a total of 100 s. After forming an inclined mesa, place it in methanol solution for 3 min and acetone solution for 5 min to remove bromine methanol and photoresist. Use a step profiler to measure the edge step to determine the etching depth h at different times. The etching thickness at 100 s is 2.7 μm.

[0063] S4. Pattern the mercury cadmium telluride sample by photolithography and etching means, obtain PN junctions with different depths, place them in a low-temperature environment to measure the IV curve to determine the junction depth, and obtain the P-layer thickness d p and the N-type layer thickness d n .

[0064] The junction depth is determined by measuring the IV curve of the inclined mesa. The inclined mesa is formed by etching. Half of it has the characteristics of a PN junction, and the other part is the N-type layer. The critical thickness at which the IV curve can be detected is the junction depth.

[0065] The IV curve confirms the position of the PN junction depth, and then the specific junction depth is measured by a step profiler.

[0066] Place the P-on-N sample on a spin coater with a rotation speed of 6000 r / min. After exposure and development by a mask aligner, use ICP etching to form a PN junction device with an etching depth of 0.5 μm. Use a Keithley 4200 semiconductor parameter tester to measure the IV curve. The etching depth h corresponding to the change of the IV curve from the resistance characteristic to the diode characteristic is the junction depth, and the measurement accuracy can reach 0.05 μm, that is, the P-type layer thickness d p = 2.1 μm, the total thickness of 8 μm minus d p is the N-type layer thickness d n = 5.9 μm.

[0067] According to Equation (1) and Equation (2), perform fitting operations on the measured n, μ n , R h , d p , d n , ρ, and calculate the P-type carrier concentration p and mobility μ p calculation formula of the PN junction material.

[0068]

[0069] After calculation, the P-type carrier concentration p = 2.3×10 18 / cm 3 , and the mobility μ p = 780 cm 2 / V·s. The thickness error is also 0.05 μm.

[0070]

Comparative Example 1

[0071] The carrier concentration and mobility were measured by the layer stripping Hall method. The method steps are as follows:

[0072] S1. Inject As ions with an energy of 150 keV into the HgCdTe sample to form a P-on-N structure sample. The P-on-N structure sample uses indium pressing to lead out the Hall test electrode, connect the Hall test system, add liquid nitrogen to cool down to 77 K, the second magnetic field is ±1 T, and pass a transverse second current I x = 1 mA, and measure the longitudinal second Hall voltage V y2 . The Hall test system can directly measure the Hall coefficient R y2 of the P-on-N structure sample according to the size, thickness and the second Hall voltage V h = 3.035 cm 3 / C and the resistivity ρ = 0.35 Ω·cm.

[0073] S2. Immerse the HgCdTe sample as a whole in a 0.5% bromine methanol etching solution for 15 s, then put it into a methanol solution for 3 min and an acetone solution for 5 min to remove bromine methanol and photoresist. The etching rate is the same as that in Example 1. Therefore, the etching depth h1 = 0.41 μm can be obtained.

[0074] S3. The etched sample once uses indium pressing to lead out the Hall test electrode, connect the Hall test system, add liquid nitrogen to cool down to 77 K, the second magnetic field is ±1 T, and pass a transverse second current I x = 1 mA, and measure the longitudinal second Hall voltage V y2 . The Hall test system can directly measure the Hall coefficient R y2 of the P-on-N structure sample according to the size, thickness and the second Hall voltage V h = 3.335 cm 3 / C and the resistivity ρ = 0.41 Ω·cm.

[0075] S4. Repeat steps S2 and S3 multiple times for etching and Hall measurement until the carrier type is N-type. The etching thicknesses are 0.35μm, 0.45μm, 0.43μm, 0.34μm, and 0.36μm respectively. The thickness of the P-type layer can be obtained as 2.34μm. Calculate the Hall coefficient and resistivity for each layer to obtain the carrier mobility and concentration for each layer, and take the average. The P-type carrier concentration is 3.2±10 18 / cm 3 , and the mobility is 730 cm 2 / V·s.

[0076]

[0077] Since it is impossible to achieve continuous variation of the etching thickness and the etching rate is not uniform each time, the thickness error of the P-type layer is more than 0.3μm (determined by the layer stripping Hall measurement method. Usually, the etching depth exceeds 0.3μm each time, so the data on the change of carrier concentration within the range of 0.3μm cannot be obtained).

[0078] Regarding any numerical values mentioned in the present invention, if there is only a two-unit interval between any minimum value and any maximum value, then all values increasing by one unit from the minimum value to the maximum value are included. For example, if the amount of a component is stated, or the thickness of an N-type substrate is 1 - 100μm, it means in this specification that the values such as 2 - 99, 3 - 98... as well as 49 - 52 and 50 - 51 are specifically listed. For non-integer values, appropriate consideration can be given with 0.1, 0.01, 0.001, or 0.0001 as a unit. These are just some specifically indicated examples. In this application, in a similar manner, all possible combinations of numerical values between the listed minimum and maximum values are considered to have been disclosed.

[0079] It should be noted that the above-described embodiments are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described by referring to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than limiting words. Modifications can be made to the present invention within the scope of the claims of the present invention, and the present invention can be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein. On the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A test method for the carrier concentration and mobility of a PN junction material, characterized in that Including: S1. Perform a Hall test on the N-type substrate to obtain the carrier concentration n and mobility μ of the N-type substrate n ; S2. Dope P-type ions on the N-type substrate by using the ion implantation process to form a P-on-N structure sample, and perform Hall measurement on the P-on-N structure sample to measure the Hall coefficient R of the P-on-N structure sample h , resistivity ρ; In step S3, the P-on-N structure sample obtained in corrosion step S2 is corroded to form an inclined surface, and the corrosion depth h is measured. S4. Then, determine the junction depth using the IV curve to obtain the thickness d of the P layer in the P-on-N structure p and the thickness d of the N-type layer n ; P-type carrier concentration p and mobility μ of the PN junction material p The calculation formulas are shown as the following formulas (1) and (2) respectively: Among them, d in the above formula (1) and formula (2) p is the thickness of the P layer, and d n is the thickness of the N-type layer, q is the electronic charge, n is the carrier concentration of the N-type substrate, and μ n is the mobility of the N-type substrate, R h is the Hall coefficient of the P-on-N structure sample, and ρ is the resistivity.

2. The test method according to claim 1, wherein The N-type substrate includes any one of mercury cadmium telluride, vanadium oxide, indium gallium arsenide, and indium antimonide. And / or, the P-type ion includes any one of As ions, Cu ions, Ag ions, and Au ions.

3. The test method according to claim 2, characterized in that The N-type substrate is mercury cadmium telluride. And / or, the P-type ion is As ion. And / or, the thickness of the N-type substrate is 1-100 μm; the length is 0.1-100 mm; The width is 0.1-100 mm; And / or, the energy of the P-type ion implantation is 60 - 500 KeV; the dose is 10 11 - 10 16 / cm 2 .

4. The test method according to claim 3, wherein The thickness of the N-type substrate is 1-50 μm; the length is 10-50 mm; the width is 10-50 mm; And / or, the energy of the P-type ion implantation is 100-180 KeV.

5. The test method according to claim 4, wherein The thickness of the N-type substrate is 2-10 μm.

6. The testing method according to claim 5, characterized in that, The thickness of the N-type substrate is 3-9 μm.

7. The test method according to any one of claims 1-6, characterized in that, The step of forming the inclined surface in step S3 includes coating photoresist on the edge of the P-on-N structure sample, immersing it in bromine methanol etching solution, immersing it downward by 0.01-5 mm every 0.1-10 s. After the inclined surface is formed, the etching solution and photoresist on the surface are removed, and methanol and / or acetone are used to clean and remove the etching solution and photoresist on the sample surface.

8. The test method according to claim 7, characterized in that, The concentration of the bromine methanol etching solution is 0.1-30 wt%.

9. The test method according to any one of claims 1-6, characterized in that Before measuring the IV curve in step S4, the P-on-N structure sample also undergoes patterning treatment.

10. The test method according to any one of claims 1-6, characterized in that, In step S1, the Hall test is carried out in a Hall test system, and the Hall coefficient R of the material is measured by the Van der Pauw method h , and the resistivity ρ.

11. The test method according to claim 10, characterized in that, The Hall measurement is performed by passing a first current through an N-type substrate under the action of a first magnetic field perpendicular to the N-type substrate, and measuring a first Hall voltage V y1 , and the Hall measurement system calculates the N-type carrier concentration n and the mobility μ n .

12. The test method according to claim 11, wherein The magnetic field strength of the first magnetic field is 0 - 10 T, and the current intensity I of the first current x1 is 0 - 10 mA.

13. The test method according to any one of claims 1-6, characterized in that, In step S2, indium is pressed on the P-on-N structure sample to lead out electrodes and connected to a Hall test system for Hall testing.

14. The test method according to claim 13, characterized in that, The Hall test is performed under the action of a second magnetic field perpendicular to the P-on-N structure sample. A second current passes through the P-on-N structure sample, and the second Hall voltage V is measured. y2 The Hall test system calculates the Hall coefficient R of the P-on-N structure sample. h and the resistivity ρ.

15. The testing method according to claim 14, wherein The magnetic field strength of the second magnetic field is 0 - 10 T, and the current intensity I of the second current x2 is 0 - 10 mA.

16. The test method according to any one of claims 1-6, characterized in that, In step S4, the P-on-N structure sample corroded in step S3 is coated with glue, lithographically developed, and then etched. The IV curve corresponding to the P-on-N structure sample is measured using a semiconductor parameter tester.

17. The test method according to claim 16, characterized in that, The depth of the etching is 0.01-10 μm; and / or, the junction depth corresponding to the IV curve changes from a resistance characteristic to a diode characteristic.

18. The testing method according to claim 16, characterized in that, The measuring instrument for measuring the corrosion depth h of the inclined surface is a profiler; And / or, the instrument for coating glue is a glue coater; And / or, the instrument for lithographic development is a lithography machine; And / or, the etching is ICP etching; And / or, the semiconductor parameter tester is a Keithley 4200 semiconductor parameter tester.

19. Application of the method for testing the carrier concentration and mobility of the PN junction material according to any one of claims 1-18 in the field of infrared detectors.

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