Method and system for measuring under-gate electron mobility of high electron mobility transistor

Abstract

The invention discloses a method and a system for measuring the under-gate electron mobility of a high-electron-mobility transistor, and mainly relates to the technical field of integrated circuit engineering. Comprising the following steps: testing gate-source currents corresponding to different gate-source voltages to obtain a first relational graph; based on the first relation graph, performing linear fitting to obtain gate-source resistance; testing gate-drain currents corresponding to different gate-drain voltages to obtain a second relational graph; based on the second relation graph, performing linear fitting to obtain gate-drain resistance; calculating the total resistance of the channel; and calculating the under-gate electron mobility. The method has the beneficial effects that the interference of parasitic resistance and contact resistance on migration rate extraction is effectively eliminated, and the calculation accuracy is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of integrated circuit engineering, and particularly relates to a method and system for measuring the electron mobility under the gate of an enhancement-mode AlGaN / GaN high electron mobility transistor. BACKGROUND

[0002] The enhancement-mode AlGaN / GaN high electron mobility transistor is an outstanding representative of a new generation of wide-bandgap semiconductor devices, and has a broad market application prospect in high-frequency and high-power fields such as power grid systems and new energy vehicles due to its high saturated electron drift speed, high breakdown voltage and other superior performances.

[0003] Research shows that the electron mobility under the gate has an important influence on the device performance of the enhancement-mode AlGaN / GaN high electron mobility transistor in high frequency and high power. Therefore, it is crucial to obtain the electron mobility under the gate of the enhancement-mode AlGaN / GaN high electron mobility transistor conveniently and accurately for improving the device performance.

[0004] At present, the split capacitance-voltage method is the most commonly used method for testing the electron mobility of the transistor, and the average electron mobility of the entire drain-source channel can be obtained through the test method. For example, in 2017, Kazuto Ohsawa et al. published the article Dependence of electron mobility on gate voltage sweeping width and deposition temperature in MOSFETs with HfO2 / Al2O3 / InGaAs gate stacks in Japanese Journal of Applied Physics, Vol. 56, No. 04CG05, which used the split capacitance-voltage method to test the electron mobility. Since the electron mobility under the gate, the gate-source region and the gate-drain region of the enhancement-mode AlGaN / GaN high electron mobility transistor are different, the average electron mobility of the entire drain-source channel tested by the split capacitance-voltage method cannot accurately reflect the electron mobility under the gate. So far, there is no method to test the electron mobility under the gate of the enhancement-mode AlGaN / GaN high electron mobility transistor.

[0005] Therefore, it is very urgent and important to study a method for determining the electron mobility under the gate of the enhancement-mode AlGaN / GaN high electron mobility transistor. SUMMARY

[0006] The purpose of this invention is to provide a method and system for measuring the gate electron mobility of enhanced AlGaN / GaN high electron mobility transistors. This method effectively eliminates the interference of parasitic resistance and contact resistance on mobility extraction and improves the accuracy of calculation.

[0007] To achieve the above objectives, the present invention employs the following technical solution: On the one hand, a method for measuring the electron mobility under the gate of a high electron mobility transistor is provided, comprising the following steps: Step S1: Test different gate-source voltages Corresponding gate-source current This yields the first relational graph; Step S2: Based on the first relationship diagram, set the current source current as the target. corresponding Apply a voltage of 0-1V to the drain. , obtain With drain-source current The change curve was linearly fitted to obtain the gate-source resistance. ; Step S3: Test different gate-drain voltages Corresponding gate-leakage current This yields the second relational graph; Step S4: Based on the second relationship diagram, set the current source current as the target. corresponding Apply a voltage of 0-1V to the source. , obtain With drain-source current The gate-leakage resistance is obtained by linearly fitting the curve of the change. ; Step S5: Test different Drain-source current ,pass Calculate the total resistance of the channel ; Step S6: Using the formula Calculate the under-gate electron mobility, where, The gate electron mobility, For grid length, The two-dimensional electron gas density in the region below the gate. For charge quantity, This represents the gate width.

[0008] Preferably, step S1 specifically includes: Two probes of a semiconductor device parameter analyzer are respectively inserted into the source and the gate of the enhancement-mode GaN HEMT, the probe of the source is grounded, and the probe of the gate applies a voltage of 3.5V-5.5V with a voltage interval of 0.25v.

[0009] Preferably, the step S2 is specifically as follows: The probe of the source of the enhancement-mode GaN HEMT is grounded, and the probe of the gate is connected to a current source, and each of the enhancement-mode GaN HEMTs is tested. Correspondingly, In the first relationship graph obtained in the step S1, the value of the gate-source voltage corresponding to the maximum drain-source current is found. Correspondingly, The current of the current source is set to be the same as the value, and a voltage varying from 0 to 1V is applied to the drain. In the process of increasing from 0V to 1V, the drain-source current gradually increases, and the size of the drain-source current is: (1). Wherein, is the potential difference between the gate and the channel point A, since the current of the current source is a fixed value, the resistance between the gate and the channel point A is a fixed value, and is a constant.

[0010] Preferably, in the testing process, increases with the increase of the gate-source voltage, the gate-source voltage and the drain-source voltage are read out and a variation curve of the gate-source voltage - is drawn, according to formula (1), and satisfy a linear function relationship, and the slope of the linear function is . According to formula (1), the variation curve is linearly fitted, and the slope of the straight line obtained by the fitting is the value of . The above testing process is repeated, and the values of corresponding to each of 3.5V-5.5V are obtained.

[0011] Preferably, the step S3 is specifically as follows: Two probes of a semiconductor device parameter analyzer are respectively inserted into the drain and the gate of the enhancement-mode GaN HEMT, the probe of the drain is grounded, and the probe of the gate applies a voltage of 3.5V-5.5V with a voltage interval of 0.25v.

[0012] Preferably, the step S4 is specifically as follows: ​​​​The drain probe of enhancement-mode GaN HEMTs is grounded, and the gate is connected to a current source. Each one is tested. corresponding At that time, the second relationship graph obtained in step S3 was found corresponding The value sets the current magnitude of the current source to be the same as the value. With the same value, a voltage varying from 0 to 1V is applied to the source. ,exist During the process of increasing from 0V to 1V, the source-drain current As the voltage gradually increases, the magnitude of the gate voltage VGD is: (2); in, Let be the potential difference from the gate to point B of the channel. Since the current from the current source is a fixed value, the resistance from the gate to point B of the channel is also a fixed value. It is a constant.

[0013] During the testing process, along with The value increases with the increase of the gate, and the value is read out. and drain And draw - The curve of change, according to equation (2), and If the relationship satisfies a linear function, then the slope of the linear function is... The curve is linearly fitted according to equation (2), and the slope of the fitted line is... Repeat the above test process to obtain values ​​from 3.5V to 5.5V. corresponding The value of .

[0014] Preferably, step S5 specifically includes: Three probes for semiconductor device parameter analysis were attached to the drain, gate, and source of an enhancement-mode GaN HEMT. The source was grounded, the drain was connected to a voltage of 0.1V, and the gate was connected to a voltage varying from 3.5V to 5.5V with a voltage interval of 0.25V. Nine sets of drain-source current values ​​were obtained. (3) The total channel resistance of 9 groups of enhancement-type GaN HEMTs was obtained. .

[0015] On the other hand, a system is provided for measuring the gate electron mobility of a high electron mobility transistor as described above, comprising: The first test module is used to test different gate-source voltages. Corresponding gate-source current This yields the first relational graph; The gate-source resistance test module is used to: set the current source current as the target based on the first relationship diagram. corresponding Apply a voltage of 0-1V to the drain. , obtain With drain-source current The change curve was linearly fitted to obtain the gate-source resistance. ; The second test module is used to test different gate-drain voltages. Corresponding gate-leakage current This yields the second relational graph; The grid-leakage resistance tester module is used to: set the current source current as the target based on the second relationship diagram. corresponding Apply a voltage of 0-1V to the source. , obtain With drain-source current The gate-leakage resistance is obtained by linearly fitting the curve of the change. ; Total resistance test module, used for: testing different Drain-source current ,pass Calculate the total resistance of the channel ; The electron mobility calculation module is used to: utilize the formula Calculate the under-gate electron mobility, where, The gate electron mobility, For grid length, The two-dimensional electron gas density in the region below the gate. For charge quantity, This represents the gate width.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: This method is simple to operate and solves the problem of not being able to accurately determine the gate electron mobility of enhancement GaN HEMTs, which is conducive to promoting the commercialization of enhancement GaN HEMTs in the field of power conversion. Attached Figure Description

[0017] Figure 1 This is a flowchart of the method of the present invention; Figure 2 This is the invention corresponding Relationship diagram; Figure 3This invention is for testing enhanced GaN HEMTs. Schematic diagram; Figure 4 This is the invention - The change curve; Figure 5 This is the invention corresponding Relationship diagram; Figure 6 This invention is for testing enhanced GaN HEMTs. Schematic diagram; Figure 7 This is the invention - The change curve; Figure 8 When the drain voltage of the present invention is 0.1V, each corresponding value; Figure 9 This is a schematic diagram of the system structure of the present invention. Detailed Implementation

[0018] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined in this application.

[0019] In this invention, terms such as "upper," "lower," "left," "right," "front," "back," "vertical," "horizontal," "side," and "bottom" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used only to facilitate the description of the structural relationships of the various components or elements of this invention and do not specifically refer to any component or element in this invention. They should not be construed as limiting the invention.

[0020] Example: like Figure 1 As shown, this embodiment provides a method for measuring the electron mobility under the gate of a high electron mobility transistor, including: Step S1: Test different gate-source voltages Corresponding gate-source current This yields the first relational graph; Step S2: Based on the first relationship diagram, set the current source current as the target. corresponding Apply a voltage of 0-1V to the drain. , obtain With drain-source current The change curve was linearly fitted to obtain the gate-source resistance. ; Step S3: Test different gate-drain voltages Corresponding gate-leakage current This yields the second relational graph; Step S4: Based on the second relationship diagram, set the current source current as the target. corresponding Apply a voltage of 0-1V to the source. , obtain With drain-source current The gate-leakage resistance is obtained by linearly fitting the curve of the change. ; Step S5: Test different Drain-source current ,pass Calculate the total resistance of the channel ; Step S6: Using the formula Calculate the under-gate electron mobility, where, The gate electron mobility, For grid length, The two-dimensional electron gas density in the region below the gate. For charge quantity, This represents the gate width.

[0021] In this embodiment, a test is used. It is 3μm. It is 4μm. It is 10μm. For 100 μm enhanced GaNHEMTs This example illustrates the electron mobility process under the gate at 4V, but is not limited to this.

[0022] 1. Test different gate-source voltages of enhancement-mode GaN HEMTs using a semiconductor device parameter analyzer. Corresponding gate-source current During testing, the two probes of the semiconductor device parameter analyzer are respectively attached to the source and gate of the enhancement-mode GaN HEMTs. The source probe is grounded, and the gate probe is subjected to a voltage of 3.5V to 5.5V, with a voltage interval of 0.25V. The test results are obtained... corresponding Relationship diagram, test results as follows Figure 2 As shown.

[0023] 2. Testing the gate-source resistance of enhancement-mode GaN HEMTs The testing principle is as follows: Figure 3As shown, during testing, the source probes of the enhancement-mode GaNHEMTs are grounded, and the gate is connected to a current source. Each... corresponding At that time, the "test obtained in process 1" was first performed. corresponding Find in the "relationship diagram" When it is 4V Value, that is A, therefore, the current magnitude of the current source is set to... A, A voltage varying from 0 to 1V is applied to the drain. .exist During the process of increasing from 0V to 1V, the drain-source current Gradually increasing, which leads to Figure 3 The potential at point A gradually increases, and the gate voltage... The size is: (1) in, The potential difference is between the gate and channel point A. Since the current from the current source is a fixed value (already set to...), Since the resistance from the gate to point A in the channel is a fixed value, therefore It is a constant. During the test, Will follow The value increases with the increase of the gate, and the value is read out. and drain Plot the change curve, and the test results are as follows: Figure 4 As shown, according to equation (1), and The relationship satisfies a linear function, where the slope of the linear function is . Therefore, for Figure 4 The curve of change is linearly fitted according to equation (1), and the slope of the fitted line is... The value, the fitted curve is as follows Figure 4 The red straight line in the middle gives us... The resistance is 62.2Ω. Repeat the above test procedure (test each...). corresponding At that time, based on " corresponding The relationship diagram changes the current source value to the corresponding value. ), to obtain the corresponding VGS for each of 3.5V~5.5V. .

[0024] 3. Use a semiconductor device parameter analyzer to test different gate-drain voltages of enhancement-mode GaN HEMTs. Corresponding gate-leakage current During testing, the two probes of the semiconductor device parameter analyzer are respectively attached to the drain and gate of the enhancement-mode GaN HEMTs. The drain probe is grounded, and the gate probe is connected to the electrode in process 1. Under the same voltage (i.e., voltage range 3.5V~5.5V, voltage interval: 0.25V), the test results were obtained for each... corresponding Relationship diagram, test results as follows Figure 5 As shown.

[0025] 4. Testing the gate-drain resistance of enhancement-mode GaN HEMTs The testing principle is as follows: Figure 6 As shown, during testing, the drain probe of the enhancement-mode GaN HEMTs is grounded, and the gate is connected to a current source. Each... corresponding At that time, the "test obtained in process 3" was first performed. corresponding Find the relationship diagram corresponding Value, that is A, therefore, the current magnitude of the current source is set to... A, Source voltage Range and process of change 2 The voltage variation range is the same (i.e., the variation range is 0 to 1V). During the process of increasing from 0V to 1V, the drain-source current Gradually increasing, this leads to, for example Figure 6 The potential at point B gradually increases, and the gate voltage... The size is: (2) in, The potential difference is from the gate to point B of the channel. Since the current from the current source is a fixed value (already set to...), The resistance from the gate to point B of the channel is a fixed value, therefore It is a constant. During the testing process... Will follow The value increases with the increase of the gate. and drain The plotted change curves and test results are as follows: Figure 7 As shown, according to equation (2), and The equation satisfies a linear function relationship, where the slope of the function is . Therefore, a linear fit is performed on the change curve according to equation (2), and the slope of the fitted line is... The value, the fitted curve is as follows Figure 7 The red straight line in the middle gives us... It is 117Ω. Repeat the above test procedure (test each...) corresponding At that time, based on " corresponding The relationship diagram changes the current source value to the corresponding value. ), to obtain the corresponding VGD values ​​from 3.5V to 5.5V. The value of .

[0026] 5. Test the total channel resistance of enhancement-mode GaN HEMTs. During testing, three probes for semiconductor device parameter analysis were attached to the drain, gate, and source of the enhancement-mode GaN HEMTs, respectively. The source was grounded, the drain was connected to a voltage of 0.1V, and the gate was connected to a voltage varying from 3.5V to 5.5V (with a voltage interval of 0.25V). Nine sets of drain-source current values ​​were obtained. The test results are as follows Figure 8 As shown. Via: (3) The total channel resistance of 9 groups of enhancement-type GaN HEMTs can be obtained. .when At time V, A, according to equation (3), we get R = 200.6Ω.

[0027] 6. Calculate the gate electron mobility of enhancement-mode GaN HEMTs. Using the above test results, the gate electron mobility corresponding to 3.5V~5.5V is calculated using the formula: (4) In the formula For the gate length of enhanced GaN HEMTs, The two-dimensional electron gas density in the region below the gate. For charge ( C), For the gate width of enhanced GaN HEMTs, The total resistance of the channel is 1. Gate-source resistance, This refers to the gate-drain resistance. When... When V, μm, for , for C, It is 100μm. It is 200.6Ω. It is 62.2Ω. Substituting 117Ω into equation (4), the calculated under-gate electron mobility μ is: .

[0028] like Figure 9 As shown, this embodiment also provides a measurement system for the gate electron mobility of a high electron mobility transistor, comprising: The first test module is used to test different gate-source voltages. Corresponding gate-source current This yields the first relational graph; The gate-source resistance test module is used to: set the current source current as the target based on the first relationship diagram. corresponding Apply a voltage of 0-1V to the drain. , obtain With drain-source current The change curve was linearly fitted to obtain the gate-source resistance. ; The second test module is used to test different gate-drain voltages. Corresponding gate-leakage current This yields the second relational graph; The grid-leakage resistance tester module is used to: set the current source current as the target based on the second relationship diagram. corresponding Apply a voltage of 0-1V to the source. , obtain With drain-source current The gate-leakage resistance is obtained by linearly fitting the curve of the change. ; Total resistance test module, used for: testing different Drain-source current ,pass Calculate the total resistance of the channel ; The electron mobility calculation module is used to: utilize the formula Calculate the under-gate electron mobility, where, The gate electron mobility, For grid length, The two-dimensional electron gas density in the region below the gate. For charge quantity, Gate width The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. A method for measuring the electron mobility under the gate of a high electron mobility transistor, characterized in that, Includes the following steps: Step S1: Test different gate-source voltages Corresponding gate-source current This yields the first relational graph; Step S2: Based on the first relationship diagram, set the current source current as the target. corresponding Apply a voltage of 0-1V to the drain. , obtain With drain-source current The change curve was linearly fitted to obtain the gate-source resistance. ; Step S3: Test different gate-drain voltages Corresponding gate-leakage current This yields the second relational graph; Step S4: Based on the second relationship diagram, set the current source current as the target. corresponding Apply a voltage of 0-1V to the source. , obtain With drain-source current The gate-leakage resistance is obtained by linearly fitting the curve of the change. ; Step S5: Test different Drain-source current ,pass Calculate the total resistance of the channel ; Step S6: Using the formula Calculate the under-gate electron mobility, where, The gate electron mobility, For grid length, The two-dimensional electron gas density in the region below the gate. For charge quantity, This represents the gate width.

2. The method for measuring the gate electron mobility of a high electron mobility transistor according to claim 1, characterized in that, Step S1 specifically includes: Two probes from a semiconductor device parameter analyzer are attached to the drain and gate of an enhancement-mode GaN HEMT. The drain probe is grounded, and the gate probe is subjected to a voltage of 3.5V to 5.5V with a voltage interval of 0.25V.

3. The method for measuring the gate electron mobility of a high electron mobility transistor according to claim 1, characterized in that, Step S2 specifically includes: For enhancement-mode GaN HEMTs, the source probe is grounded and the gate is connected to a current source. Each one is tested. corresponding At that time, the first relation graph obtained through the test in step S1 is found to be... corresponding The value sets the current magnitude of the current source to be the same as the value. With the same value, a voltage varying from 0 to 1V is applied to the drain. ,exist During the process of increasing from 0V to 1V, the source-drain current Gradually increase The size is: （1）； in, Let be the potential difference between the gate and point A of the channel. Since the current from the current source is a fixed value and the resistance between the gate and point A of the channel is a fixed value, then... It is a constant.

4. The method for measuring the gate electron mobility of a high electron mobility transistor according to claim 3, characterized in that, During the testing process, along with The value increases with the increase of the gate, and the value is read out. and drain And draw - The curve of change, according to equation (1), and If the relationship satisfies a linear function, then the slope of the linear function is... The curve is linearly fitted according to equation (1), and the slope of the fitted line is... Repeat the above test process to obtain values ​​from 3.5V to 5.5V. corresponding The value of .

5. The method for measuring the gate electron mobility of a high electron mobility transistor according to claim 1, characterized in that, Step S3 specifically includes: Two probes from a semiconductor device parameter analyzer are attached to the source and gate of an enhancement-mode GaN HEMT. The source probe is grounded, and the gate probe is subjected to a voltage of 3.5V to 5.5V with a voltage interval of 0.25V.

6. The method for measuring the gate electron mobility of a high electron mobility transistor according to claim 5, characterized in that, Step S4 specifically includes: The drain probe of enhancement-mode GaN HEMTs is grounded, and the gate is connected to a current source. Each one is tested. corresponding At that time, the second relationship graph obtained in step S3 was found corresponding The value sets the current magnitude of the current source to be the same as the value. With the same value, a voltage varying from 0 to 1V is applied to the source. ,exist During the process of increasing from 0V to 1V, the drain-source current As the voltage gradually increases, the magnitude of the gate voltage VGD is: （2）； in, Let be the potential difference from the gate to point B of the channel. Since the current from the current source is a fixed value, the resistance from the gate to point B of the channel is also a fixed value. It is a constant. During the testing process, along with The value increases with the increase of the gate, and the value is read out. and drain And draw - The curve of change, according to equation (2), and If the relationship satisfies a linear function, then the slope of the linear function is... The curve is linearly fitted according to equation (2), and the slope of the fitted line is... Repeat the above test process to obtain values ​​from 3.5V to 5.5V. corresponding The value of .

7. The method for measuring the gate electron mobility of a high electron mobility transistor according to claim 1, characterized in that, Step S5 specifically includes: Three probes for semiconductor device parameter analysis were attached to the drain, gate, and source of an enhancement-mode GaN HEMT. The source was grounded, the drain was connected to a voltage of 0.1V, and the gate was connected to a voltage varying from 3.5V to 5.5V with a voltage interval of 0.25V. Nine sets of drain-source current values ​​were obtained. （3） The total channel resistance of 9 groups of enhancement-type GaN HEMTs was obtained. .

8. A system for measuring the electron mobility under the gate of a high electron mobility transistor as described in any one of claims 1-7, characterized in that, include: The first test module is used to test different gate-source voltages. Corresponding gate-source current This yields the first relational graph; The gate-source resistance test module is used to: set the current source current as the target based on the first relationship diagram. corresponding Apply a voltage of 0-1V to the drain. , obtain With drain-source current The change curve was linearly fitted to obtain the gate-source resistance. ; The second test module is used to test different gate-drain voltages. Corresponding gate-leakage current This yields the second relational graph; The grid-leakage resistance tester module is used to: set the current source current as the target based on the second relationship diagram. corresponding Apply a voltage of 0-1V to the source. , obtain With drain-source current The gate-leakage resistance is obtained by linearly fitting the curve of the change. ; Total resistance test module, used for: testing different Drain-source current ,pass Calculate the total resistance of the channel ; The electron mobility calculation module is used to: utilize the formula Calculate the under-gate electron mobility, where, The gate electron mobility, For grid length, The two-dimensional electron gas density in the region below the gate. For charge quantity, This represents the gate width.

Images