Interface modification method of gallium oxide field effect transistor device based on self-assembly monomolecular layer
By self-assembly single-molecule layer modifying the interface of the gallium oxide field effect transistor device, the problem of metal and semiconductor interface defects in harsh environments is solved, the performance and stability of the device are improved, and suitable for high temperature, high humidity and oxidation environments.
Patent Information
- Application Number
- CN202510641061.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-19
- Publication Date
- 2025-08-19
AI Technical Summary
The prior art is difficult to effectively reduce the metal and semiconductor interface defects of gallium oxide field effect transistor devices under harsh environments, resulting in insufficient device performance and stability and unable to meet practical application needs.
The interface of the gallium oxide field effect transistor device is modified by self-assembly single-molecular layer. By photolithizing the electrode pattern on the Ga2O3 film, the single-molecular layer material is soaked, the single-molecular layer is self-assembled and the metal electrode is evaporated, and the photoresist is finally removed to form an optimized electrode-Ga2O3 interface.
It effectively reduces defects at the interface between metal and semiconductors, improves the performance and stability of the device, enhances the tolerance in high temperature, high humidity and oxidation environments, and achieves large-area and low-cost modification.
Smart Images
Figure CN120512902A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of semiconductor thin films and devices, and in particular relates to an interface modification method for a gallium oxide field-effect transistor device based on a self-assembled monolayer. Background Art
[0002] As the semiconductor industry enters the sub-10nm node era, the rapid development of modern information technology and artificial intelligence has led to the increasing integration of nanoelectronic devices, while also exposing them to complex and demanding operating environments. On the one hand, the high integration of nanotransistor devices is accompanied by increasingly concentrated localized heat generation, often causing the devices to operate in locally high-temperature environments. On the other hand, in fields such as wearable electronics, automotive electronics, military equipment, and aerospace, nanoelectronic devices must adapt to complex operating environments such as high temperature, high humidity, and oxidation. Therefore, there is an urgent need to develop new nanoelectronic materials and devices that can withstand these harsh environments.
[0003] Compared to previous generations of semiconductors, gallium oxide semiconductors offer advantages such as ultra-wide bandgap, high electron mobility, high breakdown field strength, high Baliga figure of merit, low on-resistance, and high radiation resistance. These advantages hold great potential for application in a new generation of high-efficiency, high-power power electronics, potentially breaking through physical limitations and generating revolutionary device principles and technologies. Ga₂O₃ also possesses excellent chemical, mechanical, and thermal stability. The strong charge transfer between Ga and O ions prevents dangling bonds from causing excess electrons to interact with adventitious water or oxygen molecules. Ga₂O₃'s inherent resistance to oxidation and stability in humid environments holds great promise for application in electronic devices designed to withstand harsh environments. However, the environmental tolerance of Ga₂O₃ electronic devices remains a major drawback. This is primarily due to the fact that conventional metal electrode deposition can damage the Ga₂O₃ semiconductor and introduce defects at the electrode-Ga₂O₃ interface, resulting in Fermi-level pinning and high Schottky barriers. Consequently, the electrode interface often fails before the channel material under harsh conditions. Furthermore, under high temperatures, the metal will further diffuse into the defective channel material, reducing the device's on / off ratio. Optimizing the metal electrode-Ga2O3 semiconductor interface has become a key issue that must be addressed to improve the charge transfer efficiency and device performance of field-effect transistors.
[0004] In recent years, researchers have developed many strategies to reduce barrier height to improve device performance, including the use of low-work-function metals, the insertion of buffer layers, and the transfer of metal electrodes. However, these methods cannot overcome the problem of electrode interface failure in nanodevices in harsh environments. In contrast, the transferred graphene forms a van der Waals heterojunction with Ga2O3, which can avoid chemical disorder and Fermi pinning effect, retain the properties of Ga2O3 itself, and thus reduce the defect density at the electrode-Ga2O3 interface, which is an effective method to improve the performance of Ga2O3 devices. However, the residues in the transfer process inevitably damage the semiconductor and electrode, the transfer process is cumbersome and requires complex alignment, and the transfer efficiency is low, which cannot meet the large-scale integration of devices in practical applications. Moreover, in harsh environments, some active gas molecules (such as water molecules in humid environments) may be embedded in the larger van der Waals gap, increasing the contact barrier and generating severe carrier scattering, causing the performance of Ga2O3 devices to degrade. Summary of the Invention
[0005] To overcome the shortcomings of the above-mentioned prior art, the present invention aims to provide an interface modification method for gallium oxide field-effect transistor devices based on self-assembled monolayers. The first purpose is to effectively reduce defects at the interface through sophisticated electrode interface design to improve device performance and stability. The second purpose is to solve the problem that the harsh environmental tolerance of Ga2O3 electronic devices is difficult to meet the needs of practical applications.
[0006] In order to achieve the above object, the technical solution adopted by the present invention is:
[0007] A method for modifying the interface of a gallium oxide field-effect transistor device based on a self-assembled monolayer comprises the following steps:
[0008] Step 1: Photolithography of an electrode pattern on a Ga2O3 film, followed by immersion in an aqueous solution of a monolayer material, whereby the monolayer material self-assembles on the Ga2O3 film;
[0009] Step 2: evaporating a metal electrode on the Ga2O3 film that has completed the monolayer self-assembly;
[0010] Step 3: removing the photoresist to obtain a field effect transistor device in which the monomolecular layer is introduced only on the electrode pattern.
[0011] In one embodiment, the photolithography electrode pattern on the Ga2O3 thin film is implemented as follows:
[0012] Using ultraviolet light and negative photolithography, the photoresist is removed in the areas not exposed to ultraviolet light, exposing the Ga2O3 film, while the photoresist remains on the surface of the Ga2O3 film in the areas exposed to ultraviolet light.
[0013] In one embodiment, the monolayer material is alkylthiol, aromatic thiol, alkylsilane, aminosilane, long-chain carboxylic acid, alkylphosphonic acid, amines, alcohols, PDDA, PEI or 4-mercapto-N,N-dimethylaniline.
[0014] In one embodiment, the mass fraction of the aqueous solution of the monolayer material is in the range of 0.1%-0.5%.
[0015] In one embodiment, the Ga2O3 film is immersed in the aqueous solution of the monomolecular layer material for 1-5 minutes.
[0016] In one embodiment, the thickness of the monolayer material self-assembled on the Ga2O3 film is in the range of 1-5 nm.
[0017] In one embodiment, the self-assembly can be performed by immersing in cycles according to the thickness of the self-assembled monolayer.
[0018] In one embodiment, in the cyclic immersion self-assembly, the type of monomolecular layer material and / or mass fraction and / or immersion time of the aqueous solution of the monomolecular layer material circulated may be different from those of the previous one.
[0019] In one embodiment, in step 2, the evaporated metal electrode includes Ni, Ti / Au / , or In / Au.
[0020] In one embodiment, in step 3, the Ga2O3 film having the evaporated electrode is immersed in acetone to remove the photoresist.
[0021] The gallium oxide field-effect transistor device prepared by the present invention can be used in a high temperature environment not exceeding 300° C., a high humidity environment not exceeding 100% (generally exceeding 5%), and an oxidizing environment not exceeding 50% (generally exceeding 0%).
[0022] Compared with the prior art, the present invention has the following beneficial effects:
[0023] 1. By designing a self-assembled monolayer at the electrode interface, the defects at the metal-semiconductor interface of the Ga2O3 field-effect transistor are effectively reduced to improve the performance and enhance the stability of the device.
[0024] 2. By optimizing the metal electrode-Ga2O3 semiconductor interface, the problem of Ga2O3 electronic devices' ability to withstand harsh environments can be solved to meet the needs of practical applications.
[0025] 3. The metal and semiconductor interface modification of large-area Ga2O3 field-effect transistor devices can be achieved at low cost through self-assembled monolayers. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Figure 1 Schematic diagram of the electrode-Ga2O3 interface structure modified by self-assembled monolayers (SAMs).
[0027] Figure 2 Schematic diagram of the electrode-Ga2O3 interface structure without SAMs modification.
[0028] Figure 3 Schematic diagram of the main components of self-assembled monolayer materials. DETAILED DESCRIPTION
[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.
[0030] The present invention provides an interface modification method for gallium oxide field-effect transistor devices based on self-assembled monolayers. The method utilizes self-assembled monolayer materials to modify the electrode-Ga2O3 interface, thereby reducing the Schottky barrier, preventing metal diffusion and molecular intercalation, and improving the device performance of Ga2O3 field-effect transistor devices in harsh environments.
[0031] The preparation process of the present invention is specifically described as follows:
[0032] Step 1: Use negative resist to photolithography an electrode pattern on the Ga2O3 film: the photoresist is removed in the areas not exposed to UV light, exposing the Ga2O3 film, while the photoresist remains on the surface of the Ga2O3 film in the areas exposed to UV light.
[0033] Step 2, self-assembling a monolayer on the electrode pattern: immersing the Ga2O3 film in an aqueous solution of the monolayer material, and the monolayer material self-assembles on the surface of the Ga2O3 film.
[0034] The monolayer materials used in the present invention include alkyl mercaptans (such as 1-octadecyl mercaptan), aromatic mercaptans (such as 4-mercaptophenol), alkyl silanes (such as octadecyltrichlorosilane), aminosilanes (such as 3-aminopropyltriethoxysilane), long-chain carboxylic acids (such as stearic acid), alkyl phosphoric acids (such as octadecylphosphoric acid), amines (such as dodecylamine), alcohols (such as dodecanol), PDDA, PEI, and 4-mercapto-N,N-dimethylaniline. The mass fraction of the self-assembled monolayer aqueous solution ranges from 0.1% to 0.5%. Due to the electrostatic interaction between Ga2O3 and the monolayer materials, a monolayer film of the monolayer material forms on the surface of the Ga2O3 film during immersion.
[0035] The Ga2O3 film is immersed in the aqueous solution of the monolayer material for 1-5 minutes, and the thickness of the formed self-assembled monolayer ranges from 1-5 nm. The thickness of the self-assembled monolayer can be adjusted by cyclically performing step 2.
[0036] Step 3: Vapor-deposit a metal electrode on the electrode pattern area of the Ga2O3 thin film prepared in step 2. The vapor-deposited metal electrode includes Ni, Ti / Au / , In / Au, etc.
[0037] In step 4, the Ga2O3 thin film with the electrode deposited in step 3 is soaked in acetone to remove the photoresist, ultimately resulting in a field-effect transistor device with a monolayer incorporated only on the electrode pattern of the Ga2O3 thin film. The introduction of the self-assembled monolayer reduces defects at the metal-semiconductor interface and the Schottky barrier in the field-effect transistor, while also preventing metal diffusion and molecular intercalation, facilitating the construction of a Ga2O3 field-effect transistor device capable of operating in high-temperature, humid, and oxidizing environments.
[0038] The following is a specific example of using self-assembled monolayers to modify the interface of Ga2O3 field effect transistors:
[0039] The electrode-Ga2O3 interface structure modified by self-assembled monolayer can be referred to Figure 1 As shown, inserting a self-assembled monolayer into the metal and semiconductor interface of a Ga2O3 field-effect transistor can reduce interface defects and Schottky barriers. At the same time, the introduction of a self-assembled monolayer at the interface can prevent metal diffusion and molecular intercalation, thereby enabling efficient operation of the Ga2O3 field-effect transistor device in harsh environments.
[0040] The electrode-Ga2O3 interface without self-assembled monolayer modification is as follows Figure 2 As shown in the figure, the electrode deposition process will damage the Ga2O3 semiconductor, increase interface defects and Schottky barriers. In high-temperature harsh environments, the electrode metal will diffuse into the semiconductor. In high-humidity and oxidative harsh environments, some active gas molecules (such as water molecules in humid environments and oxygen molecules in oxidative environments) will be embedded in the larger van der Waals gap, increasing the contact barrier and causing severe carrier scattering, causing the performance of the Ga2O3 device to degrade. Therefore, using self-assembled monolayers to modify the electrode-Ga2O3 interface can achieve efficient operation of Ga2O3 field-effect transistor devices in harsh environments.
[0041] The preparation method of the field effect transistor device of this structure is: first, photoetching an electrode pattern on a Ga2O3 semiconductor, then adsorbing a single molecule solution on the electrode pattern, and finally evaporating the electrode.
[0042] Furthermore, using the same mass fraction and different head group functional groups ( Figure 3A monolayer material solution containing surface-binding molecular ends (e.g., alkyl, nitro, hydroxyl, and amino groups) self-assembles on the surface of a Ga2O3 semiconductor. Monolayers of varying concentrations and numbers are assembled on the electrode to create Ga2O3 semiconductors with varying monolayer thicknesses. By optimizing the optimal monolayer material and thickness, Ga2O3 field-effect transistors (FETs) are constructed through processes such as evaporation, photolithography, and etching. Ultimately, these devices are resistant to harsh environments such as high temperature, high humidity, and oxidation.
Claims
1. A method for modifying the interface of a gallium oxide field effect transistor device based on a self-assembled monolayer, characterized in that: The steps include: Step 1: Photolithography of an electrode pattern on a Ga2O3 film, followed by immersion in an aqueous solution of a monolayer material, whereby the monolayer material self-assembles on the Ga2O3 film; Step 2: evaporating a metal electrode on the Ga2O3 film that has completed the monolayer self-assembly; Step 3: removing the photoresist to obtain a field effect transistor device in which the monomolecular layer is introduced only on the electrode pattern.
2. The method for interface modification of a gallium oxide field effect transistor device based on a self-assembled monolayer according to claim 1, characterized in that: The method for photolithography of the electrode pattern on the Ga2O3 film is as follows: Using ultraviolet light and negative photolithography, the photoresist is removed in the areas not exposed to ultraviolet light, exposing the Ga2O3 film, while the photoresist remains on the surface of the Ga2O3 film in the areas exposed to ultraviolet light.
3. The method for interface modification of a gallium oxide field effect transistor device based on a self-assembled monolayer according to claim 1, characterized in that: The monolayer material is alkylthiol, aromatic thiol, alkylsilane, aminosilane, long-chain carboxylic acid, alkylphosphoric acid, amines, alcohols, PDDA, PEI or 4-mercapto-N,N-dimethylaniline.
4. The method for interface modification of a gallium oxide field effect transistor device based on a self-assembled monolayer according to claim 1 or 3, characterized in that: The mass fraction of the aqueous solution of the monomolecular layer material is in the range of 0.1% to 0.5%.
5. The method for modifying the interface of a gallium oxide field effect transistor device based on a self-assembled monolayer according to claim 1, characterized in that: The Ga2O3 film is immersed in the aqueous solution of the monomolecular layer material for 1-5 minutes.
6. The method for modifying the interface of a gallium oxide field effect transistor device based on a self-assembled monolayer according to claim 1, characterized in that: The thickness of the monolayer material self-assembled on the Ga2O3 film is in the range of 1-5 nm.
7. The method for interface modification of a gallium oxide field effect transistor device based on a self-assembled monolayer according to claim 1 or 6, characterized in that: According to the thickness of the self-assembled monolayer, the self-assembly was performed by cyclic immersion.
8. The method for interface modification of a gallium oxide field effect transistor device based on a self-assembled monolayer according to claim 7, characterized in that: In the cyclic immersion self-assembly, the type of monomolecular layer material and / or the mass fraction and / or the immersion time of the aqueous solution of the monomolecular layer material cyclically used are different from those of the previous one.
9. The method for interface modification of a gallium oxide field effect transistor device based on a self-assembled monolayer according to claim 1, characterized in that: In the step 2, the evaporated metal electrodes include Ni, Ti / Au / , and In / Au.
10. Use of the gallium oxide field effect transistor device prepared according to claim 1 in a high temperature environment not exceeding 300°C, a high humidity environment not exceeding 100%, and an oxidizing environment not exceeding 50%.