Study On Structure Optimization And Circuit Model Of Nanoscale Vacuum Channel Transistor

Vacuum electronic devices are limited by their size,vacuum packaging and high-voltage operation,and cannot be integrated and miniaturized.In recent years,with continuous development of micro-nano processing technology,the miniaturization of vacuum electronic devices has regained researchers' interest.Advanced micro-nano processing technology reduced the size of the vacuum channel to nanoscale,which is much smaller than the mean free path of electrons in the atmosphere.While inheriting the advantages of traditional vacuum electronic devices,nanoscale vacuum channel devices have greatly improved the fabrication and circuit compatibility with solid-state devices and have potential to become a new type of integrated vacuum electronic device with significant advantages on high frequency,radiation resistance and high reliability.Based on the full-back-gate nanoscale vacuum channel transistor,the structure and materials are optimized through simulation and test.Moreover,the relationship between the frequency characteristics and structure is studied.Then the small signal equivalent circuit model is proposed.The research and the results in this thesis are listed:The morphology of the source electrode is optimized by reducing the radius of curvature,greatly increasing field enhancement factor.The aligned gate structure is proposed to reduce working voltage,improve output current and enhance control capability.Then the frequency characteristics of the device are studied based on the optimization of the DC characteristics.The influence of channel size,gate morphology,gate dielectric layer thickness and material,and static operating point on the cut-off frequency and maximum oscillation frequency is analyzed.The cut-off frequency and maximum oscillation frequency of planar nanoscale vacuum channel transistor have been improved.It is expected to make a breakthrough in terahertz devices.The small signal equivalent circuit model is preliminarily studied.The application of RF amplification and improvement ideas are proposed.In addition,according to the fabrication and test of devices,the extraction methods and steps of the parasitic and intrinsic parameters of the small signal equivalent circuit model are studied.