Method for obtaining high-performance aluminum oxide IGO / IGZO laminated thin film transistor through defect mutual compensation mechanism
By regulating the atomic layer deposition and magnetron sputtering process parameters, high-quality alumina IGO/IGZO stacked thin film transistors were prepared. The defect mutual compensation mechanism was used to solve the problem of insufficient stability of a-IGZO thin film transistors in the air, and the high mobility and high stability were achieved.
Patent Information
- Application Number
- CN202510717462.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-29
- Publication Date
- 2025-08-26
AI Technical Summary
The existing a-IGZO thin film transistors are insufficient in air stability, and it is difficult to break through the compromise relationship between mobility and stability.
By regulating the process parameters of atomic layer deposition and magnetron sputtering, high-quality alumina IGO/IGZO stacked thin film transistors are prepared, and passivation process parameters are optimized to improve device performance using the defect mutual compensation mechanism.
It achieves a balance between high mobility and high stability, overcomes the technical bottleneck of poor stability in air, and improves the performance of the device.
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Abstract
Description
Technical Field
[0001] The present invention belongs to the field of semiconductor technology, and in particular relates to a method for obtaining a high-performance aluminum oxide IGO / IGZO stacked thin film transistor through a defect mutual compensation mechanism. Background Art
[0002] The emergence of amorphous indium gallium zinc oxide (a-IGZO) in 2003 opened up a new era for amorphous oxide semiconductors. In its amorphous state, this material boasts a carrier mobility exceeding 5 cm²·V⁻¹·s⁻¹. Its dense film structure, flat surface, and high transparency in the visible light region make it an ideal semiconductor material for next-generation flexible transparent thin-film transistors (TFTs). In 2004, Nomura's team fabricated transparent a-IGZO TFTs on a flexible substrate using a near-room temperature process. The device achieved a mobility of 10 cm²·V⁻¹·s⁻¹, a threshold voltage of approximately 1 V, and an on / off ratio of 10³. This achievement strongly demonstrated the promising prospects of oxide semiconductors, particularly multi-component oxides, in TFT applications, and sparked a wave of research and development of amorphous oxide TFTs among display manufacturers worldwide.
[0003] Since then, related research has continued to make breakthroughs. In 2013, Jun Yong Bak and others from Kyung Hee University in South Korea found that adjusting the oxygen partial pressure during magnetron sputtering of IGO thin films can effectively improve the mobility and stability of the device, indicating that optimizing the film composition and deposition parameters is the key to improving device performance. In 2017, Professor Zhang Shoujin's research group used dual-target sputtering technology to prepare double-layer IGO thin-film transistors, achieving a mobility of 53.2 cm²V⁻¹S⁻¹, a subthreshold swing of 0.19 V / decade, and a capacitance of about 10 7 The on-off ratio of double-layer IGO film was confirmed for the first time, which proved the significant advantage of double-layer IGO film as an active layer. In the same year, Professor Jin-Seong Park's team at Hanyang University in South Korea used atomic layer deposition (ALD) technology to prepare IGO film. The resulting device had a mobility of 9.45 cm²V⁻¹S⁻¹, a threshold voltage of -1.57 V, and a subthreshold swing of 0.26 V / decade. The precise control characteristics of ALD technology provide a feasible solution for the large-area preparation of display devices.
[0004] In 2019, Yen-Chi Cheng et al. at National Cheng Kung University in Taiwan introduced nitrogen doping into IGO thin films and discovered that moderate nitrogen doping can reduce oxygen vacancies, improve device forward bias stability, and passivate interface trap states, providing a new strategy for enhancing device stability. In 2021, Zhu Boyu's team at South China University of Technology successfully fabricated highly stable thin-film transistors by doping a-IGO thin films with the rare earth element praseodymium. Jin-Seong Park's team at Hanyang University in South Korea further optimized ALD technology, employing plasma-enhanced atomic layer deposition (PEALD), achieving a device field-effect mobility of 36.7 cm²V⁻¹S⁻¹, a threshold voltage of -5.5 V, and a subthreshold swing of 0.3 V / decade. In 2023, Jie Zhang et al. at Purdue University in the United States used ALD to fabricate ultrathin a-IGO thin-film transistors approximately 3 nm thick, achieving a mobility of 28.6 cm²V⁻¹S⁻¹. This demonstrated for the first time the high performance and three-dimensional integration potential of IGO TFTs at microscale.
[0005] Currently, one of the technical bottlenecks in the TFT field is insufficient stability in air, which in turn affects mobility. To overcome this problem, researchers will exploit the defect mutual compensation mechanism to successfully create a device with both high mobility and high stability. Summary of the Invention
[0006] Technical problem to be solved: In view of the technical problem in the prior art that a-IGZO thin-film transistor technology is difficult to overcome the compromise between mobility and stability, the present invention provides a high-performance aluminum oxide IGO / IGZO thin-film transistor and a preparation method thereof, which regulates the growth process, growth temperature and thickness of the thin film deposition by atomic layer deposition technology to obtain a high-quality aluminum oxide gate insulating layer, and regulates the growth temperature, gas pressure and power of magnetron sputtering to prepare high-quality aluminum oxide IGO / IGZO thin films to obtain devices with excellent performance. By comparing IGO / IGZO thin-film transistors prepared under different aluminum oxide passivation conditions, the passivation mechanism and the growth process parameters with the best device performance obtained in combination with passivation are explored, and the process parameters of magnetron sputtering are adjusted to obtain high-quality aluminum oxide IGO / IGZO thin-film transistors.
[0007] The present invention provides a method for obtaining a high-performance aluminum oxide IGO / IGZO stacked thin film transistor using a defect mutual compensation mechanism, comprising: (1) preparing a silicon wafer as a substrate material; (2) regulating the growth process, growth temperature and thickness of the thin film deposition by atomic layer deposition technology to prepare a high-quality aluminum oxide gate insulating layer on the substrate; (3) regulating the growth temperature, gas pressure and power of magnetron sputtering to prepare a high-quality IGO / IGZO thin film; (4) evaporating metal source and drain electrodes to obtain an IGO / IGZO thin film transistor; (5) using the IGO / IGZO thin film transistor prepared by aluminum oxide passivation again, exploring the passivation mechanism and the growth process parameters for the best device performance obtained by passivation; and (6) adjusting the process parameters of magnetron sputtering while maintaining good device performance to obtain a high-performance IGO / IGZO thin film transistor.
[0008] Preferably, the process temperature of the atomic layer deposition technology is 100~300℃, the total deposition pressure is 0.4~5.1Pa, the pulse gas pressure of water for growing alumina is 3.9~6.8 kPa, and the pulse duration is 10~30 s; nitrogen is cyclically introduced with a pressure value of 1.2~4.1 Pa, 3 s~4 s, and a pressure value of 5.2~6.8 Pa, 3 s~4 s as a cycle, or nitrogen is cyclically introduced with a pressure value of 5.2~6.8 Pa, 3 s~4 s, and stopped for 3 s~4 s as a cycle.
[0009] Preferably, a small amount of ammonia gas is introduced after the conventional atomic layer deposition steps, with a flow rate of 100-200 sccm and a duration of 3-7 seconds. This addition can significantly reduce the operating voltage of IGO / IGZO thin-film transistors and improve their stability. This is presumably because ammonia reacts with the aluminum oxide surface to form aluminum oxide nitride (AlN) or aluminum nitride (AlNx), altering the surface morphology of the aluminum oxide passivation layer and, consequently, the passivation effect.
[0010] Preferably, the growth temperature of magnetron sputtering is 100-300°C, the gas pressure is 0.4-5.1 Pa, the oxygen partial pressure is 1-5%, the oxygen purity is above 99.99%, and the back vacuum is controlled to be 5-10×10 -5 Pa, the sputtering power is 50-200 W, and the sputtering time is 5-300 min. Most preferably, the magnetron sputtering power is 150 W, and the deposition time is 10 min.
[0011] Preferably, the ammonia gas flow rate for passivating the IGO / IGZO thin film transistor is 100-200 sccm, and the flow time is 3-7 s. The direction of the first nitrogen gas flow is at an angle of 4-7 degrees to the surface of the IGO / IGZO thin film substrate.
[0012] Principle of defect mutual compensation mechanism: In IGO / IGZO films, oxygen vacancies, as typical donor defects, dominate. Their ionization process can release two free electrons, thereby significantly increasing the carrier concentration. However, when excess oxygen in the environment penetrates into the interior of the film, it can capture electrons as an acceptor defect to form O²⁻ (Oex + 2e⁻ → O²⁻), resulting in unexpected annihilation of carriers. These two types of defects form a dynamically competing charge compensation network in the film. Donor-type VO tends to increase conductivity, while acceptor-type Oex induces carrier scattering and localization. The presence of these two defects seriously interferes with the directional movement of free electrons, which manifests as increased device hysteresis and a significant decrease in bias stability.
[0013] Beneficial effects: The defect mutual compensation mechanism proposed in the present invention obtains a high-performance alumina IGO / IGZO stacked thin film transistor preparation technology. The process temperature is maintained at 100~300 degrees Celsius. The passivation process is adopted and the defect mutual compensation mechanism is utilized to effectively improve the stability of the device, overcome the problem of poor stability hindering the technological progress of the industry, and obtain a high-performance alumina IGO / IGZO stacked film. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 The transfer characteristic curve of the device before and after passivation in Example 1 under a sputtering pressure of 0.5 Pa and a deposition time of 10 min is shown in FIG. Figure 2 The transfer characteristic curve of the device before and after passivation in Example 1 under a sputtering pressure of 0.7 Pa and a deposition time of 10 min is shown in FIG. DETAILED DESCRIPTION
[0015] In order to more clearly describe the present invention and facilitate understanding, the specific technical methods in the embodiments of the invention are described in detail below. It should be noted that the present invention is not limited to the specifically mentioned implementation methods, and the implementation methods of the present invention are not limited to this. Modifications or equivalent substitutions to the present invention should all be covered within the scope of the claims of the present invention. Example
[0016] A method for obtaining a high-performance aluminum oxide IGO / IGZO stacked thin film transistor using a defect mutual compensation mechanism comprises the following steps: (1) Selecting a silicon wafer as the substrate; (2) The atomic layer deposition technology growth process and process temperature were controlled to 200°C, the film thickness was 21-25 nm, and finally a small amount of ammonia gas was introduced at a flow rate of 100 sccm for 6 s to obtain a high-quality aluminum oxide gate insulating layer on the silicon wafer; (3) The growth temperature of magnetron sputtering was controlled to 200 °C, the pressure to 0.5 Pa and the power to 100 W, and the back vacuum to 5 × 10 -5 Pa is used to prepare high-quality IGO / IGZO thin films and obtain devices with excellent performance; (4) Evaporating metal source and drain electrodes to obtain IGO / IGZO thin film transistors; (5) The IGO / IGZO thin film transistor prepared by aluminum oxide passivation is again used, and the passivation growth process parameters are the same as step (2). Example
[0017] A method for obtaining a high-performance aluminum oxide IGO / IGZO stacked thin film transistor using a defect mutual compensation mechanism comprises the following steps: (1) Selecting a silicon wafer as the substrate; (2) The atomic layer deposition technology growth process and process temperature were controlled to 300°C, the film thickness was 21-25 nm, and finally a small amount of ammonia gas was introduced at a flow rate of 150 sccm for 4 s to obtain a high-quality aluminum oxide gate insulating layer on the silicon wafer; (3) The growth temperature of magnetron sputtering was controlled to 200 °C, the pressure to 0.7 Pa and the power to 100 W, and the back vacuum to 5 × 10 -5 Pa is used to prepare high-quality IGO / IGZO thin films and obtain devices with excellent performance; (4) Evaporating metal source and drain electrodes to obtain IGO / IGZO thin film transistors; (5) The IGO / IGZO thin film transistor prepared by aluminum oxide passivation is again used, and the passivation growth process parameters are the same as step (2).
[0018] In the examples of the present invention, it is necessary to continuously control the atomic layer deposition technology growth process, growth temperature, and thickness of the film deposition to obtain a high-quality aluminum oxide gate insulation layer; by controlling the growth temperature, gas pressure, and power of magnetron sputtering, high-quality IGO / IGZO thin films are prepared, and devices with excellent performance are prepared. By comparing IGO / IGZO thin-film transistors prepared under different aluminum oxide passivation conditions, the passivation mechanism and the growth process parameters that achieve the best device performance with passivation are explored. While maintaining good device performance, the magnetron sputtering process parameters are adjusted to obtain high-performance IGO / IGZO thin-film transistors. The obtained IGO / IGZO films have high mobility and high stability.
Claims
1. A method for obtaining a high-performance alumina IGO / IGZO stacked thin film transistor using a defect mutual compensation mechanism, characterized in that: The steps include: (1) Preparing a silicon wafer as a substrate material; (2) Regulating the atomic layer deposition technology growth process, growth temperature and film deposition thickness to prepare a high-quality aluminum oxide gate insulation layer on the substrate; (3) Regulating the growth temperature, pressure, and power of magnetron sputtering to prepare high-quality IGO / IGZO films; (4) Evaporating metal source and drain electrodes to obtain IGO / IGZO thin film transistors; (5) Using IGO / IGZO thin film transistors prepared by aluminum oxide passivation, we explored the passivation mechanism and the growth process parameters that optimize device performance with passivation. (6) While maintaining good device performance, the process parameters of magnetron sputtering are adjusted to obtain high-performance IGO / IGZO thin film transistors.
2. The IGO / IGZO thin film transistor according to claim 1, characterized in that: The process temperature of the atomic layer deposition technology is 100~300℃, and the total deposition pressure is 0.4~5.1Pa.
3. The IGO / IGZO thin film transistor according to claim 2, characterized in that: The pulse gas pressure of water in the atomic layer deposition growth of aluminum oxide is 3.9~6.8kPa, and the pulse duration is 10~30 s.
4. The IGO / IGZO thin film transistor according to claim 1, wherein: The growth temperature of magnetron sputtering is 100~300℃, the gas pressure is 0.4~5.1 Pa, the oxygen partial pressure is 1~5%, and the back vacuum is controlled at 3~10×10 -5 Pa, sputtering power is 50~200W, and sputtering time is 3~300 min.
5. The IGO / IGZO thin film transistor according to claim 4, characterized in that: The oxygen purity required by the above technology is above 99.99%.
6. The IGO / IGZO thin film transistor according to claim 4, characterized in that: The magnetron sputtering gas is argon gas, and the purity of the argon gas is 99.99%.
7. The IGO / IGZO thin film transistor according to claim 1, characterized in that: The ammonia flow rate for passivating IGO / IGZO thin film transistors is 100~200 sccm, and the injection time is 3-7 s.