Preparation method of In2O3 / SnO2 double-active-layer heterojunction thin film transistor
Through the In2O3/SnO2 dual active layer heterojunction structure, the carrier transmission characteristics are optimized, the problem of insufficient performance of traditional TFTs is solved, and higher carrier mobility and electrical performance are achieved, which is suitable for high-performance electronic devices.
Patent Information
- Application Number
- CN202510401493.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-01
- Publication Date
- 2025-06-27
AI Technical Summary
Traditional thin film transistors (TFTs) with single-layer active layer structures have problems such as low carrier mobility, unstable threshold voltage, and poor environmental stability in performance, which is difficult to meet the needs of high-resolution displays, high-speed circuits and low-power devices.
The In2O3/SnO2 dual active layer heterojunction structure is adopted to prepare an active layer film by magnetron sputtering method, and the heterojunction quantum well is formed by using the energy band structure differences of In2O3 and SnO2 materials to optimize the injection, transmission and storage process of carriers.
It significantly improves the carrier capacity and electrical performance of TFT, achieves higher saturation mobility and linear mobility, and is suitable for high-performance displays, sensors and integrated circuits and other fields.
Smart Images
Figure CN120224718A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of semiconductor display, and particularly relates to a preparation method of an In2O3 / SnO2 heterojunction thin film transistor device. Background Art
[0002] With the rapid development of semiconductor technology, thin film transistors (TFTs), as core components in modern electronic devices, are widely used in fields such as electronic display, sensors, integrated circuits, etc. Traditional TFT devices usually adopt a single-layer active layer structure, which has simple processes, low cost, stable performance, and is suitable for large-area production, and is applicable to fields that are sensitive to cost and require large-area applications. However, the single-layer active layer structure has certain limitations in performance, such as low carrier mobility, unstable threshold voltage, poor environmental stability, etc., and it is difficult to meet the requirements of high-resolution displays, high-speed circuits, and low-power devices. In recent years, the heterojunction structure has gradually become an effective way to improve the performance of TFTs due to its unique energy band structure and interface characteristics. The heterojunction structure can effectively regulate the transport characteristics of carriers by forming quantum wells at the interface between two different semiconductor materials, thereby improving the electrical performance of the device. As two common oxide semiconductor materials, In2O3 has a high mobility, SnO2 has excellent environmental stability and low leakage current, and the energy band structures of these two materials are significantly different. By combining these two materials, it is expected to form a heterojunction quantum well structure to promote electron transport and further optimize the electrical performance of TFTs to meet the requirements of modern electronic devices for high-performance semiconductor devices. Summary of the Invention
[0003] To solve the above technical problems, the technical solution provided by the present invention is: a preparation method of an In2O3 / SnO2 double-active-layer heterojunction thin film transistor, comprising the following steps:
[0004] (1) Cleaning the Si / SiO2 substrate:
[0005] Ultrasonically treat the substrate in acetone, alcohol, and deionized water for 5 - 20 minutes respectively; then dry it with a nitrogen gun for standby;
[0006] (2) Preparation of the active layer:
[0007] Prepare the active layer thin film by magnetron sputtering method, specifically including:
[0008] (2.1) Single-layer In2O3 active layer: Adopt DC sputtering, pattern it through a metal mask, and anneal it in an air atmosphere after sputtering;
[0009] (2.2) Single-layer SnO2 active layer: Direct current sputtering is used and patterned through a metal mask; after sputtering, annealing is carried out in an air atmosphere;
[0010] (2.3) In2O3 / SnO2 active layer: First, the In2O3 layer is sputtered, and then the SnO2 active layer is continuously sputtered on the sputtered In2O3 layer, both patterned through a metal mask; after sputtering, annealing is carried out in an air atmosphere;
[0011] (2.4) SnO2 / In2O3 active layer: First, the SnO2 active layer is sputtered, and then the In2O3 active layer is continuously sputtered on the sputtered SnO2 layer, both patterned through a metal mask; after sputtering, annealing is carried out in an air atmosphere;
[0012] (3) Preparation of the electrode layer:
[0013] For the electrode part, a metal evaporation and plating instrument is used to deposit an aluminum electrode on the prepared sample, and the source and drain electrodes are patterned through a metal mask.
[0014] Preferably, in step (2.1), the conditions for direct current sputtering of the single-layer In2O3 active layer are: argon gas flow rate is 10 - 30 sccm, oxygen gas flow rate is 30 - 40 sccm, working pressure is 0.2 - 0.5 Pa, the film thickness is controlled to be 5 - 20 nm, and the annealing temperature is 250 - 400 °C.
[0015] Preferably, in step (2.2), the conditions for direct current sputtering of the single-layer SnO2 active layer are: argon gas flow rate is 0 - 20 sccm, oxygen gas flow rate is 30 - 50 sccm, working pressure is 0.2 - 1.0 Pa, the film thickness is controlled to be 5 - 20 nm, and the annealing temperature is 250 - 400 °C.
[0016] Preferably, in step (2.3), the sputtering conditions for sputtering the In2O3 layer in the In2O3 / SnO2 active layer are: argon gas flow rate is 10 - 30 sccm, oxygen gas flow rate is 30 - 40 sccm, working pressure is 0.2 - 0.5 Pa, the film thickness is controlled to be 2.5 - 10 nm; the sputtering conditions for continuously sputtering the SnO2 active layer are: argon gas flow rate is 0 - 20 sccm, oxygen gas flow rate is 30 - 50 sccm, working pressure is 0.2 - 1.0 Pa, the film thickness is controlled to be 2.5 - 10 nm, and the annealing temperature is 250 - 400 °C.
[0017] Preferably, in step (2.4), the sputtering conditions for the SnO2 active layer in the SnO2 / In2O3 active layer are as follows: the argon flow rate is 0 - 20 sccm, the oxygen flow rate is 30 - 50 sccm, the working pressure is 0.2 - 1.0 Pa, and the film thickness is controlled to be 2.5 - 10 nm; the sputtering conditions for continuously sputtering the In2O3 active layer are: the argon flow rate is 0 - 20 sccm, the oxygen flow rate is 30 - 50 sccm, the working pressure is 0.2 - 1.0 Pa, the film thickness is controlled to be 2.5 - 10 nm, and the annealing temperature is 250 - 400 °C.
[0018] The advantages of the present invention compared with the prior art are as follows:
[0019] (1) The In2O3 / SnO2 heterojunction TFT proposed by the present invention has significant performance advantages; due to the advantages of the heterojunction structure, the In2O3 / SnO2 heterojunction TFT prepared by the present invention realizes a significant increase in the carrier capacity; this structure optimizes the processes of carrier injection, transport, and storage, thereby increasing the carrier concentration inside the device, manifested as higher saturation mobility and linear mobility; the improvement of these performances enables the device to have a broader application prospect in the fields of high-performance display, sensors, integrated circuits, etc.
[0020] (2) The In2O3 / SnO2 heterojunction TFT of the present invention can achieve optimized preparation at a relatively low temperature (250 - 400 °C); this low-temperature preparation process not only reduces the production cost but also reduces the risk of thermal damage to the substrate material, which is beneficial to the preparation of devices on large-area and flexible substrates.
[0021] (3) The preparation process of the In2O3 / SnO2 heterojunction TFT of the present invention is relatively simple and easy to integrate into the existing production process; the simplified process steps help to improve production efficiency, reduce manufacturing costs, and are beneficial to the large-scale production of devices.
[0022] In summary, by adopting the In2O3 / SnO2 heterojunction structure, the present invention not only improves the carrier capacity and electrical properties of the TFT but also realizes a low-temperature and simplified preparation process, providing new ideas and methods for the development of high-performance oxide semiconductor devices. This not only helps to promote the development of oxide semiconductor technology but also will promote the upgrading of related electronic products to meet the market demand for high-performance displays and intelligent devices. Description of the Drawings
[0023] Figure 1 It is a schematic diagram of the device structure of the present invention.
[0024] Figure 2 shows the present invention at the drain-source voltage V DSWhen V = 0.1V, the transfer characteristic curves and the extracted linear mobility curves of single-layer In2O3, single-layer SnO2, In2O3 / SnO2 heterojunction, and SnO2 / In2O3 heterojunction TFTs.
[0025] Figure 3 shows the present invention at a drain-source voltage V DS = 10.1V, the extracted saturation mobility curves of the transfer characteristic curves of single-layer In2O3, single-layer SnO2, In2O3 / SnO2 heterojunction, and SnO2 / In2O3 heterojunction TFTs.
[0026] Figure 4 is the saturation mobility and linear mobility diagram of single-layer In2O3, single-layer SnO2, In2O3 / SnO2 heterojunction, and SnO2 / In2O3 heterojunction TFTs of the present invention. Detailed implementation manners
[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention.
[0028] Embodiment 1:
[0029] Combined with the attached Figure 1-4 , this embodiment discloses a preparation method of an In2O3 / SnO2 double active layer heterojunction thin film transistor, including the following steps:
[0030] (1) Cleaning the Si / SiO2 substrate:
[0031] Ultrasonically process the substrate in acetone, alcohol, and deionized water for 5 - 20 minutes respectively; then dry it with a nitrogen gun for standby;
[0032] (2) Preparation of the active layer:
[0033] Use magnetron sputtering to prepare the active layer thin film, specifically including:
[0034] (2.1) Single-layer In2O3 active layer: Use DC sputtering, the argon flow rate is 10 - 30 sccm, the oxygen flow rate is 30 - 40 sccm, the working pressure is 0.2 - 0.5 Pa, control the film thickness to be 5 - 20 nm, and pattern it through a metal mask; after sputtering, anneal it in an air atmosphere, and the annealing temperature is 250 - 400 °C;
[0035] (2.2) Single-layer SnO2 active layer: DC sputtering is used, with the argon flow rate being 0 - 20 sccm, the oxygen flow rate being 30 - 50 sccm, the working pressure being 0.2 - 1.0 Pa, controlling the film thickness to be 5 - 20 nm, and patterning is carried out through a metal mask; after sputtering, annealing is performed in an air atmosphere, and the annealing temperature is 250 - 400 °C;
[0036] (2.3) In2O3 / SnO2 active layer: First, the In2O3 layer is sputtered, and the sputtering conditions are the same as those for the single-layer In2O3 sputtering above, controlling the film thickness to be 2.5 - 10 nm; then, on the sputtered In2O3 layer, the SnO2 active layer is continuously sputtered, and the sputtering conditions are the same as those for the single-layer SnO2 active layer above, controlling the film thickness to be 2.5 - 10 nm; both are patterned through a metal mask; after sputtering, annealing is performed in an air atmosphere, and the annealing temperature is 250 - 400 °C;
[0037] (2.4) SnO2 / In2O3 active layer: First, the SnO2 active layer is sputtered, and the sputtering conditions are the same as those for the single-layer SnO2 active layer above, controlling the film thickness to be 2.5 - 10 nm; then, on the sputtered SnO2 layer, the In2O3 active layer is continuously sputtered, and the sputtering conditions are the same as those for the single-layer In2O3 sputtering above, controlling the film thickness to be 2.5 - 10 nm; both are patterned through a metal mask; after sputtering, annealing is performed in an air atmosphere, and the annealing temperature is 250 - 400 °C.
[0038] (3) Preparation of the electrode layer:
[0039] For the electrode part, a metal evaporation and plating instrument is used to deposit an aluminum electrode on the prepared sample, and patterning of the source and drain electrodes is carried out through a metal mask.
[0040] Combined with the attached Figure 1 , the attached Figure 1 is a schematic diagram of the device structure of the present invention; from bottom to top, they are an n-type Si substrate (gate), a SiO2 insulating layer, an In2O3 active layer, a SnO2 active layer, and an aluminum electrode layer;
[0041] Combined with Figure 2, in Figure 2, A and B are respectively the transfer characteristic curves and the extracted linear mobility curves of single-layer In2O3, single-layer SnO2, In2O3 / SnO2 heterojunction, and SnO2 / In2O3 heterojunction TFTs when the drain-source voltage V DS = 0.1 V. It can be seen that it is difficult to turn off the single-layer SnO2 TFT and the SnO2 / In2O3 TFT. Although the single-layer In2O3 TFT can be turned off, the threshold voltage is still relatively negative and the on-state current is not high enough. The In2O3 / SnO2 heterojunction TFT has relatively optimal comprehensive performance;
[0042] Combined with Figure 3, A and B in Figure 3 are the saturation mobility curves extracted from the transfer characteristic curves of single-layer In2O3, single-layer SnO2, In2O3 / SnO2 heterojunction, and SnO2 / In2O3 heterojunction TFTs when the drain-source voltage V DS = 10.1V; as V DS increases, the drain current I D of all TFTs also increases correspondingly. This is because at a higher V DS , the current driving ability of the device is enhanced. Additionally, like V DS = 0.1V, the In2O3 / SnO2 heterojunction TFT has relatively optimal comprehensive performance;
[0043] Combined with the attached Figure 4 , the attached Figure 4 is the saturation mobility and linear mobility diagram of single-layer In2O3, single-layer SnO2, In2O3 / SnO2 heterojunction, and SnO2 / In2O3 heterojunction TFTs; it can be seen that whether it is the saturation mobility or the linear mobility, the In2O3 / SnO2 heterojunction TFT shows more excellent performance; this may benefit from the complementarity of the material characteristics of In2O3 and SnO2 and the matching of the energy band structures; on the one hand, a heterojunction quantum well is formed at the interface between the two, which can effectively reduce scattering and promote electron transport; on the other hand, In2O3 located in the front channel intrinsically has a high electron mobility; under the combined action of these two, the In2O3 / SnO2 heterojunction TFT device exhibits the optimal comprehensive electrical performance of the TFT;
[0044] As can be seen from the above, the specific electrical parameters of the single-layer In2O3, single-layer SnO2, In2O3 / SnO2 heterojunction, and SnO2 / In2O3 heterojunction TFTs of the present invention are shown in the following table:
[0045]
[0046] The above describes the present invention and its implementation manners. This description is not restrictive, and what is shown in the drawings is only one of the implementation manners of the present invention. The actual structure is not limited thereto. Generally speaking, if those of ordinary skill in the art are inspired by it and without departing from the purpose of the present invention creation, and design similar structural manners and embodiments to this technical solution without creative efforts, they should all fall within the protection scope of the present invention.
Claims
1. A method for preparing an In2O3 / SnO2 double active layer heterojunction thin film transistor, characterized in that: The following steps are involved: (1) Cleaning Si / SiO2 substrate: The substrate was ultrasonically treated in acetone, alcohol, and deionized water for 5-20 minutes respectively; Then use a nitrogen gun to blow dry and set aside; (2) Preparation of active layer: The active layer film is prepared by magnetron sputtering method, which specifically includes: (2.1) Single-layer In2O3 active layer: Direct current sputtering is used, patterning is performed through a metal mask, and annealing is performed in air atmosphere after sputtering; (2.2) Single-layer SnO2 active layer: patterned by direct current sputtering through a metal mask; annealed in air atmosphere after sputtering; (2.3) In2O3 / SnO2 active layer: First, sputter the In2O3 layer, and then continue to sputter the SnO2 active layer on the sputtered In2O3 layer, and both are patterned through a metal mask; after sputtering, anneal in air atmosphere; (2.4) SnO2 / In2O3 active layer: First, the SnO2 active layer is sputtered, and then the In2O3 active layer is sputtered on the sputtered SnO2 layer, and both are patterned through a metal mask; after sputtering, annealing is performed in an air atmosphere; (3) Preparation of electrode layer: The electrode part uses a metal evaporation device to evaporate aluminum electrodes on the prepared sample, and pattern the source and drain electrodes through a metal mask.
2. The method for preparing an In2O3 / SnO2 double active layer heterojunction thin film transistor according to claim 1, characterized in that: In step (2.1), the conditions for DC sputtering of the single-layer In2O3 active layer are: argon flow rate is 10-30sccm, oxygen flow rate is 30-40sccm, working gas pressure is 0.2-0.5Pa, film thickness is controlled to be 5-20nm, and annealing temperature is 250-400℃.
3. The method for preparing an In2O3 / SnO2 double active layer heterojunction thin film transistor according to claim 1, characterized in that: In step (2.2), the conditions for DC sputtering of the single-layer SnO2 active layer are: argon flow rate is 0-20sccm, oxygen flow rate is 30-50sccm, working pressure is 0.2-1.0Pa, film thickness is controlled to be 5-20nm, and annealing temperature is 250-400℃.
4. The method for preparing an In2O3 / SnO2 double active layer heterojunction thin film transistor according to claim 1, characterized in that: In step (2.3), the sputtering conditions for sputtering the In2O3 layer in the In2O3 / SnO2 active layer are: argon flow rate of 10-30sccm, oxygen flow rate of 30-40sccm, working gas pressure of 0.2-0.5Pa, and the film thickness is controlled to be 2.5-10nm; the sputtering conditions for continuing to sputter the SnO2 active layer are: argon flow rate of 0-20sccm, oxygen flow rate of 30-50sccm, working gas pressure of 0.2-1.0Pa, the film thickness is controlled to be 2.5-10nm, and the annealing temperature is 250-400℃.
5. The method for preparing an In2O3 / SnO2 double active layer heterojunction thin film transistor according to claim 1, characterized in that: In step (2.4), the sputtering conditions for sputtering the SnO2 active layer in the SnO2 / In2O3 active layer are: argon flow rate of 0-20sccm, oxygen flow rate of 30-50sccm, working gas pressure of 0.2-1.0Pa, and controlling the film thickness to 2.5-10nm; the sputtering conditions for continuing to sputter the In2O3 active layer are: argon flow rate of 0-20sccm, oxygen flow rate of 30-50sccm, working gas pressure of 0.2-1.0Pa, controlling the film thickness to 2.5-10nm, and annealing temperature of 250-400℃.