Method for reducing turn-on voltage of gallium oxide diode based on hydrogen treatment

Abstract

The present invention discloses a method for reducing the turn-on voltage of a gallium oxide diode based on hydrogen treatment, mainly solving the problem of the high turn-on voltage of existing gallium oxide diodes. The solution is as follows: According to the concentration at which hydrogen is prone to explosion and the diffusion rate of hydrogen atoms in the gallium oxide material, the hydrogen concentration is selected to be 0.1% - 4% and 75.6% - 100%; Multiple gallium oxide diode devices are selected and placed in a single layer and fixed at the bottom of a storage tank and sealed, and then the selected hydrogen is filled into the storage tank until the pressure in the tank reaches 0.1 - 3 MPa; A constant temperature box device is selected, and its working temperature is set to 20 - 350 °C according to the ignition temperature of hydrogen; The storage tank filled with hydrogen and containing devices inside is placed in the constant temperature box, the power supply is turned on and left to stand for 1 - 100 days, and then the power supply is turned off and the devices are taken out, achieving the reduction of the turn-on voltage of the devices. The present invention effectively reduces the turn-on voltage of the gallium oxide diode and can be applied to high-frequency power electronic systems.

Description

Technical Field

[0001] The present invention belongs to the technical field of wide-bandgap semiconductors, and particularly relates to a method for reducing the turn-on voltage of Ga2O3 diodes, which can be used in high-frequency power electronic systems. Background Art

[0002] As a very promising semiconductor component, Ga2O3 power semiconductor devices play the roles of rectification, amplification, and switching in circuits. In the future, they can be used as power supplies for various devices, drive loads, and pulse power regulation systems of electronic devices, and have important potential application values in the fields of new energy, rail transit, aerospace, etc.

[0003] With the continuous development of the fields of space electric propulsion and power management, there is a huge demand for high-performance power electronic devices, and Ga2O3 power devices are an important choice to meet this demand. Diodes are one of the main research contents of Ga2O3 power devices. The turn-on voltage is an important device parameter of diodes. The magnitude of the turn-on voltage directly affects the switching speed and power loss of the device, and thus affects the practical application of the device. Currently, most research mainly reduces the turn-on voltage by changing the structure of diode devices.

[0004] Deng Xiaochuan et al. proposed in the patent document with the application number 202010126013.9 to fabricate a super-barrier diode by connecting a three-channel accumulation-type channel MOSFET in series with a JFET. Compared with traditional diodes, this diode adds two trench-gate vertical accumulation channels, changing from the original single-channel structure to a three-channel structure, greatly increasing the carrier density in the channel, thereby reducing the turn-on voltage of the device.

[0005] He Yunlong et al. proposed in the patent document with the application number 202111070355.4 to open grooves on the upper surface of the drift layer and fill the grooves with metal Ni, so that the metal Ni forms a Schottky contact with the Ga2O3 drift layer to control the turn-off of the device, and form an ohmic contact between the anode metal layer and the Ga2O3 drift layer to reduce the turn-on voltage of the gallium oxide Schottky power diode.

[0006] Although the above two methods can reduce the turn-on voltage of diode devices, these methods require adding process steps, with high technical difficulty, low yield, and high manufacturing cost. Summary of the Invention

[0007] The purpose of the present invention is to provide a method for reducing the turn-on voltage of gallium oxide diodes based on hydrogen treatment in view of the deficiencies of the above-mentioned existing technologies, so as to improve the device yield and reduce the manufacturing cost.

[0008] To achieve the above purpose, the technical solution of the present invention is realized as follows:

[0009] 1. Technical Principle

[0010] Hydrogen is the substance with the smallest relative molecular mass. At room temperature, the properties of hydrogen are very stable and it is not easy to chemically react with other substances. However, when conditions change, such as ignition, heating, or using a catalyst, strong reactions will occur. For example, when hydrogen is adsorbed by palladium or platinum metal, it has strong activity; when the volume fraction in the air is 4% - 75.6%, it is prone to explosion; when hydrogen molecules enter the crystal lattice of a metal, the phenomenon of "hydrogen embrittlement" will occur.

[0011] Hydrogen has a wide range of uses in many fields: in medicine, high-pressure hydrogen is commonly used to treat liver parasite infections; in the chemical industry, hydrogen is often used as a special gas or chemical raw material; in the petrochemical industry, hydrogen can be used as a hydrogenating agent for shampoo, lubricants, and household cleaners; in the field of electronics manufacturing, hydrogen can be used for material modification, such as hydrogen implantation.

[0012] Based on the physical properties of hydrogen, which is small in volume and has strong activity after being catalyzed by transition metals, the present invention modifies gallium oxide materials with hydrogen to reduce the turn-on voltage of gallium oxide diodes. By setting the concentration and pressure of hydrogen, hydrogen treatment is carried out on gallium oxide diodes with an anode metal containing one or more of the transition metals Pt, Ni, Pd, Rh, and Mo in a closed storage tank, so that the highly active hydrogen atoms formed after hydrogen is catalyzed by the transition metal diffuse into the gallium oxide material, passivate the intrinsic defects on the surface of the gallium oxide material, make the contact between the anode metal and the gallium oxide material better, reduce the potential barrier at the interface of the gallium oxide diode, and thus achieve the reduction of the turn-on voltage.

[0013] 2. Technical Solution

[0014] According to the above principle, a method for reducing the turn-on voltage of a gallium oxide diode based on hydrogen treatment according to the present invention is characterized by including the following steps:

[0015] According to the concentration range of hydrogen that is prone to explosion, which is 4.0% - 75.6%, and the diffusion rate of hydrogen atoms in gallium oxide materials, a hydrogen concentration of 0.1% - 4% and 75.6% - 100% is selected.

[0016] Select multiple Ga2O3 diode devices, lay them flat in a single layer along the same circumference as the bottom of the storage tank and fix them at the bottom of the storage tank, seal the storage tank, and then fill the selected hydrogen into the storage tank through the one-way inflation port inside the storage tank until the pressure in the storage tank reaches 0.1 - 3 MPa.

[0017] Select an incubator device and set the temperature of the incubator device to 20 - 350°C according to the ignition temperature of hydrogen, which is 400°C.

[0018] After checking that the storage tank is properly sealed, place the storage tank filled with hydrogen and containing the device into the thermostat. After checking that the parameter settings of the thermostat are correct, turn on the power and keep it on until the static storage time reaches 1 to 100 days, then turn off the power and take out the device to reduce its turn-on voltage.

[0019] Preferably, the selected Ga2O3 diode must satisfy the following two conditions simultaneously:

[0020] Its anode metal must contain one or more of the transition metals Pt, Ni, Pd, Rh, and Mo;

[0021] Its anode surface is not covered by any passivation layer.

[0022] Preferably, the pressure of the hydrogen filled in the storage tank is selected according to the pressure resistance value of the sealed storage tank, that is, the pressure resistance range of the storage tank is 0.1 to 3 MPa, and thus the pressure of the hydrogen filled in the storage tank is determined to be 0.1 to 3 MPa.

[0023] The present invention does not require additional process steps, has a relatively low technical difficulty, a high yield rate, and a low manufacturing cost.

[0024] The test results show that the present invention can significantly reduce the turn-on voltage of the device. Brief Description of the Drawings

[0025] Figure 1 is the implementation flowchart of the present invention;

[0026] Figure 2 is the I-V test comparison diagram of the Ga2O3 diode before and after hydrogen treatment using the present invention at low voltages. Detailed Embodiments

[0027] The following further describes the specific examples and effects of the present invention in detail with reference to the drawings, but the implementation manners of the present invention are not limited thereto.

[0028] Refer to Figure 1 , the present invention gives the following three embodiments.

[0029] Embodiment 1, select a gallium oxide Schottky diode device with Pt in the anode metal, the hydrogen concentration is 100%, the pressure of the hydrogen filled in the gas storage tank is 0.3 MPa, set the temperature in the thermostat to 25 °C, and the storage time of the gas storage tank in the thermostat is 7 days.

[0030] Step 1, select the experimental device.

[0031] Based on the chemical property that Pt metal has strong catalytic performance and can decompose hydrogen gas on its surface into hydrogen atoms, the selected experimental device is a gallium oxide Schottky diode with Pt in the anode metal.

[0032] Step 2: Select the concentration and pressure of hydrogen gas.

[0033] According to the property that hydrogen gas is not likely to explode when its concentration is 100%, and based on the results of multiple hydrogen treatment experiments showing that hydrogen atoms diffuse relatively fast in gallium oxide materials at a hydrogen gas concentration of 100% and a pressure of 0.3 MPa, the selected hydrogen gas concentration is 100% and the pressure is 0.3 MPa.

[0034] Step 3: Place the experimental device at the bottom inside the storage tank.

[0035] 3.1) Select the number of Ga2O3 Schottky diode devices according to the area size of the bottom of the gas storage tank.

[0036] In this embodiment, the bottom shape of the gas storage tank is a circle with a diameter of 10 cm, and the selected single Ga2O3 Schottky diode device is a rectangle with dimensions of 1 cm × 1.2 cm. According to these two parameters, the number of Ga2O3 Schottky diode devices for hydrogen treatment is 60.

[0037] 3.2) Arrange the selected 60 devices in a single layer in a tiled manner within the same circular area as the bottom inside the storage tank, with the long sides adjacent to each other and the short sides adjacent to each other, and fix them to ensure that the anode region of the devices can fully contact with hydrogen gas.

[0038] Step 4: Fill the gas storage tank with hydrogen gas.

[0039] After checking the tightness of the gas storage tank and the hydrogen gas concentration, fill the storage tank with hydrogen gas with a concentration of 100% through the built-in one-way gas filling port. Stop filling when the pressure inside the gas storage tank reaches 0.3 MPa.

[0040] Step 5: Select the storage temperature and time.

[0041] Based on the property that hydrogen gas does not burn at a temperature of 25°C, and according to the results of multiple hydrogen treatment experiments showing that the turn-on voltage of the gallium oxide Schottky diode can be significantly reduced after storing for 7 days at a temperature of 25°C, the selected storage temperature is 25°C and the storage time is 7 days.

[0042] Step 6: Place the storage tank into an incubator.

[0043] After checking that the gas storage tank is properly sealed, place the storage tank filled with hydrogen and containing the device in an incubator. After checking that the parameter settings of the incubator are correct, turn on the power until the static storage time reaches 7 days, then turn off the power and take out the device to achieve a reduction in its turn-on voltage.

[0044] Example 2: Select a gallium oxide Schottky diode device with an anode metal containing Ni. The concentration of hydrogen is 2%, the pressure of the hydrogen filled in the gas storage tank is 0.3 MPa, the temperature in the incubator is set at 150 °C, and the storage time of the gas storage tank in the incubator is 88 days.

[0045] Step 1: Select the experimental device.

[0046] Based on the chemical property that Ni metal has strong catalytic performance and can decompose hydrogen on its surface into hydrogen atoms, it is determined that the selected experimental device is a gallium oxide Schottky diode with an anode metal containing Ni.

[0047] Step 2: Select the concentration and pressure of hydrogen.

[0048] Based on the property that hydrogen is not likely to explode when the concentration is 4%, and the result shown by multiple hydrogen treatment experiments that the diffusion rate of hydrogen atoms in gallium oxide material is moderate at a hydrogen concentration of 4% and a pressure of 0.3 MPa, it is determined that the selected hydrogen concentration is 4% and the pressure is 0.3 MPa.

[0049] Step 3: Place the experimental device at the bottom inside the storage tank.

[0050] The specific implementation of this step is the same as Step 3 of Example 1.

[0051] Step 4: Fill the gas storage tank with hydrogen.

[0052] After checking that the airtightness of the gas storage tank and the concentration of hydrogen are correct, fill the storage tank with hydrogen with a concentration of 4% through the one-way inflation port inside the storage tank. Stop inflation when the pressure inside the gas storage tank reaches 0.3 MPa.

[0053] Step 5: Select the storage temperature and time.

[0054] Based on the property that hydrogen does not burn at a temperature of 150 °C, and the result shown by multiple hydrogen treatment experiments that storing for 88 days at a temperature of 150 °C can significantly reduce the turn-on voltage of the gallium oxide Schottky diode, it is determined that the selected storage temperature is 150 °C and the storage time is 88 days.

[0055] Step 6: Place the storage tank in the incubator.

[0056] After checking that the gas storage tank is properly sealed, place the storage tank filled with hydrogen and containing the device in an incubator. After checking that the parameter settings of the incubator are correct, turn on the power until the static storage time reaches 88 days, then turn off the power and remove the device to achieve a reduction in its turn-on voltage.

[0057] Example 3: Select a gallium oxide Schottky diode device with an anode metal containing both Pt and Ni. The concentration of hydrogen is 100%, the pressure of the hydrogen filled in the gas storage tank is 0.5 MPa, the temperature in the incubator is set to 120 °C, and the storage time of the gas storage tank in the incubator is 4 days.

[0058] Step A: Select the experimental device.

[0059] Based on the chemical property that Pt and Ni metals have strong catalytic performance to decompose hydrogen on their surfaces into hydrogen atoms, determine that the selected experimental device is a gallium oxide Schottky diode with an anode metal containing Pt and Ni.

[0060] Step B: Select the concentration and pressure of hydrogen.

[0061] Based on the property that hydrogen is not likely to explode when the concentration is 100%, and the result shown by multiple hydrogen treatment experiments that hydrogen atoms diffuse faster in gallium oxide materials at a hydrogen concentration of 100% and a pressure of 0.5 MPa, determine that the selected hydrogen concentration is 100% and the pressure is 0.5 MPa.

[0062] Step C: Place the experimental device at the bottom inside the storage tank.

[0063] The specific implementation of this step is the same as step 3 of Example 1.

[0064] Step D: Fill the gas storage tank with hydrogen.

[0065] After checking that the gas storage tank is airtight and the hydrogen concentration is correct, fill the storage tank with hydrogen at a concentration of 100% through the one-way inflation port inside the storage tank, and stop inflation when the pressure in the gas storage tank reaches 0.5 MPa.

[0066] Step E: Select the storage temperature and time.

[0067] Based on the property that hydrogen does not burn at a temperature of 120 °C, and the result shown by multiple hydrogen treatment experiments that storing for 4 days at a temperature of 120 °C can significantly reduce the turn-on voltage of the gallium oxide Schottky diode, determine that the selected storage temperature is 120 °C and the storage time is 4 days.

[0068] Step F: Place the storage tank in the incubator.

[0069] After checking that the gas storage tank is sealed properly, place the storage tank filled with hydrogen and containing the device into an incubator. After checking that the parameter settings of the incubator are correct, turn on the power. Then turn off the power until the static storage time reaches 4 days, and take out the device to achieve a reduction in its turn-on voltage.

[0070] The effects of the present invention can be further illustrated by the following measured data:

[0071] I. Test conditions

[0072] Select a semiconductor analyzer device, set the test voltage for I-V test to be 0 - 2V, and the test accuracy to be 0.01V; II. Test content

[0073] Prepare ten gallium oxide Schottky diode devices with Pt in the anode metal of the same preparation process. Connect the positive and negative electrodes of these devices to the semiconductor analyzer device in sequence. Under the above conditions, test the I-V curve of the device before hydrogen treatment; then perform hydrogen treatment on the selected ten devices using the method of the present invention, and connect the positive and negative electrodes of these devices to the semiconductor analyzer device in sequence. Under the above conditions, test the I-V curve of the device after hydrogen treatment. The results are as Figure 2 .

[0074] It can be seen from Figure 2 that the turn-on voltage of the device before hydrogen treatment is 0.9V, and the turn-on voltage of the device after hydrogen treatment is 0.6V, indicating that the method of the present invention can reduce the turn-on voltage of the device by nearly 0.3V.

[0075] The above description is only three specific embodiments of the present invention and does not constitute any limitation to the present invention. Although for professionals in the field, after understanding the content and principle of the present invention, various modifications and changes in form and details may be made without departing from the principle and structure of the present invention. For example, in addition to Pt and Ni selected in this embodiment for the anode metal of the gallium oxide diode, it may also contain one or more of the transition metals Pd, Rh, and Mo. However, these corrections and changes based on the idea of the present invention are still within the protection scope of the claims of the present invention.

Claims

1. A method for reducing the turn-on voltage of a gallium oxide diode based on hydrogen treatment, characterized in that The steps are as follows: According to the explosion-prone hydrogen concentration range of 4.0% - 75.6% and the diffusion rate of hydrogen atoms in gallium oxide materials, select hydrogen concentrations of 0.1% - 4% and 75.6% - 100%; Select multiple Ga2O3 diode devices, lay them flat in a single layer along the same circumference as the inner bottom of the storage tank, fix them at the bottom inside the storage tank, seal the storage tank, and then fill the selected hydrogen into the storage tank through the one-way inflation port inside the storage tank until the pressure inside the storage tank reaches 0.1 - 3 MPa; The selected Ga2O3 diodes simultaneously meet the following two conditions: its anode metal must contain one or more of the transition metals Pt, Ni, Pd, Mo, Rh; its anode surface is not covered by any passivation layer; Select an incubator device, and set the temperature of the incubator device to 20 - 350°C according to the ignition temperature of hydrogen being 400°C; After checking that the sealing of the storage tank is correct, place the hydrogen-filled storage tank into the incubator. After checking that the parameter settings of the incubator are correct, turn on the power, and turn off the power until the static storage time reaches 1 - 100 days, then take out the device to achieve a reduction in its turn-on voltage.

2. The method according to claim 1, wherein: The selection of the hydrogen pressure filled inside the storage tank is based on the pressure resistance value of the sealed storage tank, that is, the pressure resistance range of the storage tank is 0.1 - 3 MPa, and thus the hydrogen pressure filled inside the storage tank is determined to be 0.1 - 3 MPa.

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