The Study Of Terahertz Power Amplifier Based On Field Emission Transistor

Terahertz waves have unique characteristics that light waves and microwaves do not have,and have broad application prospects in imaging,communications,medical treatment,and detection.However,due to the lack of high-power,low-cost,wide-band,and miniaturized terahertz sources,the development of terahertz technology is limited.Because the output power of the existing solid-state terahertz source is too low to meet the needs of further research on the terahertz device,the output signal needs to be power amplified.The nano-channel field emission transistor is a combination of traditional electric vacuum devices and solid-state devices.It has the characteristics of low noise,high power,wide bandwidth,and low cost.It is suitable as a terahertz power amplifier.As we all know,the array structure of field emission transistors determines the final output performance.The array model is usually used to optimize the array,and the array model can quickly calculate the influence of the array parameters on the output electrical parameters.However,most of the existing array models are not suitable for nano-channel lateral field emission transistors.Based on this,this thesis proposes a lateral nano-channel field emission transistor array emission model based on multiple suspended spheres,and through simulation,the effectiveness of the multi-sphere model is verified by comparison with the CST calculation results.The multi-ball model accelerates the optimization speed of the nano-channel field emission transistor array,and realizes the efficient calculation of the output current and line current density of the nano-channel field emission transistor array.Using this model,this thesis studies the array of nano-channel field emission transistors.First,a nano-channel field emission transistor array with a tapered tip is proposed.Through simulation and theoretical calculation,the electrical characteristics and cutoff frequency of the structure are obtained.Then,the cutting-edge field emission transistor was improved,and a field emission transistor with a thin film structure was proposed.The structure has good electron beam uniformity,large emission current,and sufficient high-frequency performance to work in the terahertz frequency band.On this basis,in order to improve the leakage current problem,this thesis proposes a double-gate field emission transistor,and analyzes the electrical characteristics and frequency of the structure as well as the trajectory of emitted electrons.Based on dual-gate field emission transistors,the THz band amplifier topology is designed.Finally,this article studies the fabrication process of nano-channel field emission transistors,and tries to prepare the fabrication process of nano-channel field emission transistors,and based on the experimental results,proposes an improvement plan for the adopted fabrication process.The simulation results show that the dual-gate field emission transistor has a very high cut-off frequency,can work in the terahertz frequency band,and has a high electron beam output power.The double-gate field emission transistor has a good electron beam morphology and extremely low leakage current.Using the THz signal amplifying structure constructed with double-gate field emission transistors,the simulation has realized the effects of wide bandwidth and high output power.In summary,the dual-gate field emission transistor proposed in this article provides a good solution for terahertz power amplifiers.