The Structure And Techniques Research Of GaN Power Devices In Microwave And THz

The emphasis of this work is focused on the wide-gate GaN-based power HEMTs manufacturing, GaN-based Gunn diode structure design and key process technology. On the one hand, the GaN / AlGaN wide-gate HEMT structures were manufactured. Based on the theory analysis, the author gets the reason of key factors in high-frequency high-power devices design principles. According to the different design of GaN / AlGaN HEMT devices'wide gate, the author proposes the techniques and methods of wide gate HEMT as well as the schematics of bare chip and completed GaN/AlGaN HEMT devices which are encapsulated. Meanwhile, the author takes V-I characteristics measurement for different GaN/AlGaN HEMT devices, specially, in alternative V-I measurement. The author compares to work parameters of difference GaN/AlGaN HEMT devices in different wide gate.On another side, we take some theory research on GaN-based Gunn diode structures inner mechanism, especially, the relation of velocity and electronic field. Considering conclusion as before, the relation ship of doping levels and transit region is needed to meet the condition which must be in the area between two critical limitations. The GaN-based Gunn diode structures has excellent performance over the traditional GaAs-based diode in very high-frequency and output power from the result of simulation by using SILVACO simulator.The key problem of GaN-based Gunn diode products is ohmic contact problem of GaN. For overcoming above mentioned problems, the author proposes two new process techniques to reduce the specific contact of ohmic contact resistance, one is new twice annealing. Comparing the new technique's outlook appearance and characteristics to the traditional, the new technique has more excellent properties. The other is to handle the sputtering region before making ohmic contact via aqua regia. After experiments, it seems that the use of aqua regia to boil ohmic contact region can get the lowest specific contact compared with the left tow methods: HCL and deionized water.