Gallium Nitride Based High Electron Mobily Switching Transistors And Circuits For Single Pole Double Throw Switch

Gallium nitride?GaN?as the third generation of wide band gap semiconductor material,with high thermal conductivity,high breakdown voltage,high electron drift rate,high temperature,high pressure,anti-radiation and other advantages,is especially suitable for application in the millimeter wave digital phased array radar system.T/R components are the core components of the radar system,and its performance directly affects the development of radar systems.As the front-end components in the transceiver system,the insertion loss,isolation,power capacity and other performances have a great impact on the noise figure,the output power and other performance in the entire transceiver system.In this paper,AlGaN/GaN HEMT switching devices and switching circuits as the main works of this research are summarized as follows:First,the main working principle of AlGaN/GaN HEMT switching device is studied.Switching devices mainly work in the linear region and cut-off area,respectively,corresponding to on state and off state.And the influence of different device structure on the performance of switching device is studied.The source and drain spacing of switching devices,gate width,single tube and double tube structure,single gate and double gate structure,gate resistance and other factors on insertion loss,isolation,switching time,power capacity and other performance of the switching device are included.Secondly,based on the 0.25?m gate length process of the Institute of Microelectronics,Chinese Academy of Sciences,a small signal equivalent circuit model of AlGaN/GaN HEMT switching devices is proposed.The OPEN structure test method or reverse cut-off method are introduced to extract the parasitic capacitance of the switching device.The parasitic inductance and parasitic resistance of the switching device are extracted by using the SHORT test structure method or the reverse cutoff method combined with the unbiased method.A new method of extracting the intrinsic parameters is proposed.In the5GHz-40GHz frequency band,small signal model of AlGaN/GaN HEMT switching device fits very well,and the error factor is less than 3.85%Finally,a DC-6GHz high-power single-pole double-throw switch circuit is proposed.The specific design methods,circuit topology selection,switching device selection,schematic simulation,layout and schematic simulation,layout drawing are introduced.The switching chip has been tested for DC characteristics,small signal S parameters,continuous wave power capacity,switching time and other performance indicators.The results show that IL<0.687 dB,ISO>40 dB,P_1dB=27.5 dBm,t_on=7.98 ns,t_off=8.93 ns,the size only 1.85mm×1.0 mm.