Research On GaN HEMT High-Power Microwave Switching Devices And Switching Circuits

The single-pole double-throw switch is a key part of the transmit / receive(T / R)component,which is used to control the on and off of the signal in the circuit.In recent years,with the rapid development of third-generation semiconductors such as gallium nitride(GaN),GaN HEMTs have superior performance in terms of high breakdown voltage,high electron drift rate,high power,and resistance to radiation.The device's single-pole double-throw switch will be widely used in the field of millimeter-wave active phased array radar systems and 5G base stations.The volume and high integration of the switching circuit provide great research prospects.In this context,this article combines the 0.25?m GaN HEMT technology platform independently developed by Microelectronics,and uses GaN HEMT switching devices and Ku-band single-pole double-throw switch circuits as the core.The following research results have been achieved:1.The performances and models of different device structures of GaN HEMT switching devices are analyzed in detail.The effects of different switching devices on the S parameters and power performance are studied,and the method of extracting switching device model parameters is discussed.A measure of the accuracy of the device model.Including the effects of different gate widths,source-drain spacings,and additional gate resistances on small signals and power capacity,and guiding the design of switching circuits;establishing a small signal model suitable for GaN HEMT switching devices,and obtaining parasitic and intrinsic parameters of the model.The model fitting error factor is less than 2.56%,and the model fits well.2.Based on the 0.25?m GaN HEMT device process independently developed by Microelectronics,an ultra-thin In Al N / GaN / Si HEMT Schott with a wide bias range of-30 <VR <0V and a wide temperature of 273K-473 K was studied before and after the gate trench process.Based on the reverse leakage mechanism,a trap-assisted tunneling mechanism(TAT)is proposed as the main leakage mechanism of ultra-thin In Al N / GaN / Si HEMT.The extracted trap state energy level ?t,activation energy Ea,and X-ray photoelectron spectroscopy(XPS)results confirm that the nitrogen plasma surface treatment technology can be used to optimize the Schottky interface state,thereby reducing Schottky reverse leakage.Furthermore,by slowly modifying the formula of the electric field in the high reverse bias region,the phenomenon that the TAT current increases slowly in the high field region is theoretically analyzed.3.Based on the analysis of the switching device and process,a multi-parallel multi-level topology was used to optimize the design of multiple single-pole double-throw switch circuits,and the simulation results met the design indicators.And the test method is researched.On-chip test results show that at 12GHz-18 GHz,input and output return loss is greater than 10 dB,insertion loss is less than 1.2dB,isolation is greater than 30 dB,input power P1 dB is greater than 42.2dBm(16.6W),and test performance Meet the design requirements,the chip area is 2.37 mm × 1.60 mm.