Construction And Logic Circuits Application Exploration Of Indium Oxide Based Thin Film Transistors

Thin film transistor（TFT）is a key component in flat panel display（FPD）applications.With the development of electronic devices,the performance of oxide-based TFT has gradually improved and demonstrate potential application prospects in some special areas,such as full flexible display and wearable display.Indium oxide（In₂O₃）has been widely studied as one of the most excellent active layers of TFT due to high electron mobility,excellent transparency,good uniformity and stability.It is of great significance to investigate the preparation of high-performance low voltage-driving TFT based on In₂O₃,optimize the device performance and reduce the device preparation temperature.At the same time,using high dielectric constant material（high-k）as dielectric layer instead of traditional SiO₂ can reduce the working voltage and power consumption of TFT and optimize the device performance.In this paper,the process temperature and device performance are optimized by exploring novel high k dielectric layer combined with two-dimension material controlling active layer.Based on MXene-doped indium oxide as the active layer of TFT,this paper explores the replacement of traditional SiO₂by a new cerium oxide as the dielectric layer of TFT to optimize the performance of TFT devices,and investigates the application of TFT in logic circuit resistance load inverter.The results demonstrate that the intercalation of Ti₃C₂T_x MXene and the construction of In₂O₃homogeneous active layer can not only improve the performance of In₂O₃ TFTs,but also effectively reduce the device preparation temperature to adapt to the mainstream trend of modern flat panel displays,expanding the application of TFT in flexible display and wearable display.The results show that the prepared TFT has the advantages of high mobility,low process temperature,low driving voltage and high stability.Besides,low temperature prepared TFT has been successfully used in logic circuit resistance load inverter.The main results of the paper are as follows:1.Based on the combination of solution method and ALD technology,CeO₂/Al₂O₃laminated gate is constructed,and the feasibility of Al₂O₃ passivated CeO₂ as the gate dielectric layer of thin film transistor is verified.The results show that 300℃annealed In₂O₃/Al₂O₃/CeO₂TFT presents high performances with saturation mobility of 18.74 cm²/V·s and remarkable positive bias stress stability.Furthermore,In₂O₃/Al₂O₃/CeO₂ TFT based resistor-loaded inverter is further fabricated with good voltage transfer characteristics and behaves with voltage gain of12.81 at 5 V.These experimental results demonstrate In₂O₃ TFTs based on Al₂O₃/CeO₂ as high-k dielectric have potential application value in low-voltage driver and logic circuit.2.Based on the solution method and doping process,In₂O₃/Al₂O₃/CeO₂ TFTs are constructed,and the effect of rare earth element Gd doping on the properties is investigated.It is found that 30%Gd doping can effectively prevent oxygen vacancy related defects and leakage current in CeO₂ films,the constructed TFT demonstrates best performances with I_on/I_offratio of 1.45×10⁷,saturation mobility of 27.28 cm²/V·s,subthreshold swing of 0.091 V/decade,as well as remarkable positive bias stress stability.Moreover,a resistor-loading inverter based on Al₂O₃/CeGdO_x-gated TFT exhibits superior voltage transfer characteristics with a voltage gain of 16 at 5 V.The research results show that the In₂O₃/Al₂O₃/CeGdO_x TFTs based on the rare earth doping process demonstrated potential application prospects in ultra-stable and future digital circuits.3.Based on ALD technology and the two-dimensional material Ti₃C₂T_x MXene intercalation process,the low temperature fabrication of low voltage driven high-performance In₂O₃ TFTs devices has been realized.ALD method is used to prepare the Al₂O₃ dielectric layer at 200℃,Ti₃C₂T_x MXene intercalation is introduced between the Al₂O₃ dielectric layer and the In₂O₃ active layer to construct the In₂O₃/MXene/Al₂O₃ thin film transistor.The electrical properties are optimized by changing the concentration of MXene to adjust the connectivity of the spin-coated film nanosheets.The results demonstrate that Al₂O₃/MXene/In₂O₃ TFT at a concentration 2 mg/m L MXene has the best performance with the mobility of 15.41 cm²/V·s and significant bias stress stability.The resistance load inverter based on In₂O₃/MXene/Al₂O₃TFT has a gain of up to 11.6 at 5 V,and shows good voltage transmission characteristics,which conforms to the operation rules of logic"NOT gate".Low-frequency noise is applied to analysis the mechanism of MXene intercalation into the active layer/dielectric layer interface to improve device performance.The experimental results show that MXene intercalation structure can effectively improve the performance parameters and operational stability of In₂O₃-based thin film transistors,and also provide a reliable experimental path and solution for device performance optimization.4.Based on the MXene doping process,the low temperature construction of MXene-In₂O₃/In₂O₃ homojunction TFTs has been realized.MXene is further used to optimize TFTs,the homojunction based on Ti₃C₂T_x MXene-doped In₂O₃ is realized in high-performance and low temperature-preparation thin film transistors（TFTs）.It is found that doping of MXene into In₂O₃ results in n-type semiconductor behavior,realizing tunable work function of In₂O₃ from5.11 to 4.79 eV as MXene content increases from 0 to 2 wt%.MXene doped In₂O₃-based homojunction TFT presents optimal performance with electron mobilities of greater than 27.10cm²/V·s at 240℃.The improved performance originates from boosting of a two-dimensional electron gas（2DEG）formed at carefully engineered In₂O₃/MXene doped In₂O₃ oxide homojunction interface.Besides,the transformation in conduction mechanism leads to better stability of MXene doped In₂O₃ homojunction devices compared to undoped bilayer In₂O₃.Low-frequency noise further illustrates that doping MXene into In₂O₃ helps to reduce the device trap density of device.A resistor-loaded unipolar inverter based on In₂O₃/0.5%MXene-In₂O₃TFT has demonstrated full swing characteristics and a high gain of 13.These experimental results demonstrate the effective doping of MXene provides an effective strategy for the design of a new type of homogeneous junction thin film transistor for low-cost oxide based electronic devices.