Research Of High Frequency And Microwave Bipolar Power Devices

High-frequency and microwave bipolar power devices have been largely applied in military and civil electronic equipment, mainly in communication, radar (including navigation) and electron-confrontation field. Since the parameter of full-solid electronic equipment such as volume, weight, property, price and reliability etc. mostly depends on high-frequency and microwave bipolar power transistors and their amplifiers, so it has great value and practical significance to devices their property. On the basis of operating-characteristic of high-frequency and microwave bipolar power devices, this paper proposes new structures and new materials which helps to improve devices' property, detaily analyzes their distinguishing feature and function, completes corresponding experiments, and obtains important theoretical and experimental data. The main works are as the follows.In view of the contradiction among frequency, output power and dissipation power, propose deep-trench junction termination structure filling with isolated materials and collector-combed (base-combed) structure. Using two-dimensional numerical simulation software, analyze the affect of isolated-trench's parameters on the breakdown voltages of three-class bipolar power devices(whose ideal breakdown voltages correspond to 40V, 70V and 100V), which include width, depth, isolated material's dielectric constant, fixed interface-charge and field plate located at the top of deep-trench termination. The simulation results indicate, deep-trench junction termination with certain width, depth and filling with isolated dielectric can increase the avalanche breakdown voltage of devices to above 95% of the ideal value. The BVCBO and BVCEO of DCT260 that has deep-trench termination structure are respectively 66V and 32V, which are separately 94% and 92% of ideal values, add to 9V and 6V than 3DA260 with traditional termination structure. And the results of calculation and numerical simulation indicate, without increasing the intrinsic collector-junction area of power devices, collector-combed structure helps to raise the intrinsic heat-dissipating area and base's perimeter, improve heat-dissipating method of each cell of the chip, enhance the distribution uniformity of junction temperature and current of each cell of the chip, reduce the thermalresistance and raise the dissipation power PD and output power P0, fairly well relax the contradiction among frequency, out-put power and dissipation power of the devices, and further improve the devices' property against second breakdown. Experimental sample DCT375 with collector-combed structure has better parameter such as ICM, PQ, PD and/r etc. than traditional-structure devices and overseas devices of the same kind. Collector-combed structure technology opens up a new way for the further research of new high-frequency, microwave power devices.In order to improve bipolar power devices' reliability, propose not-uniform two-direction ballasting technology and overload-temperature defending technology with V-class thermistor film. Theoretical analysis indicates, the two technology helps reduce the concentration of current, lower the peak junction-temperature, and effectively avoid the appearance of devices' breakdown caused by heat and current. Experimental results show, with the not-uniform two-direction ballasting technology, the peak junction-temperature at the center of the chip can be lessened 7-10 surface temperature of the case can also reduce 3-7, and the heat-dissipating property of the power devices has distinct improvement. V-class thermistor film is successfully produced on silicon substrate and SiO2 substrate applying CVD process for the first time in this paper, whose minimum thickness is only 600nm or so. Experimental results prove, this film has an infinite resistance within 90 temperature, but its resistance will suddenly drop once the temperature is over 100, and at 150 temperature, its Rm/Rm,a is over 700 times. The film resistance parallel-connected between the emitter and the base of power dev...