A Study Of The Structure And The Performance Of Microwave Silicon Bipolar Transistor Using For MMIC And Its Process Development

The silicon bipolar technology holds the important status in the field of super high-speed integrated circuit, and the reason is the bipolar device has stronger driving force, bigger transconductance and quicker speed compared to the MOS components. A series of new bipolar device structure and the processing technology developed in recent years successfully caused the Si bipolar circuit speed to develop amazingly.In this paper, we have designed the double-polysilicon emitter structure which base on the traditional transistors and the single-polysilicon emitter structure, and developed the processing technology according to the structure. The main features of this structure is that has reduced the horizontal dimensions of transistor and the parasitic capacitance by making the outside-base built on the thick oxide layer and two layers of polysilicon build-up in the form of vertical overlap. The key advantages over conventional bipolar technology are: based on standard CMOS technology platform for manufacturing, ultra-light emitter, deep trench isolation, the twice concentration of boron injection technology and other advanced technology, to create higher transition frequencies, higher power gain, lower noise, better heat dissipation, simpler matching, higher integration. The test results showed that with the processes used in this article, the gain bandwidth product fT of the transistor have achieved about 20GHz which is tested at IC=25mA,VCE=2V,f=2GHz. The noise figure tested at IC=2mA,VCE=2V,f=2GHz have achieved 1.2dB which is better than the level of similar foreign products. And the value of︱S21︱2 tested at IC=25mA,VCE=2V,f=2GHz have achieved 15dB.However, due to ability and time limited, we have not been able to ponder meticulous and achieved completeness. The difficulty of manufacturing process technology have made a gap between the gain bandwidth product fT of the transistor which is made with the processing technology described in this paper and the theoretical value, also the current capacity is still insufficient which can be improved in optimizes and process in future process.