Technology Research On Silicon Germanium Heterojunction Bipolar Transistors And Low Noise Amplifiers

The rapid development of mobile communication, radar, GPS and high speed data processsystem stimulates a lot of demands to high-performance semiconductor devices greatly in recentyears, semiconductor devices turn to high frequency, low voltage, low power consumption, lownoise, small size and low cost application. Compared with Si devices and Ⅲ-Ⅴcompoundsemiconductor devices, the SiGe technology products with higher performance-cost ratio cater tothe development needs of market and become the hot field in the semiconductor world.Foreign research and development departments of large companies have studied SiGetechnology for many years, IBM has pushed much products into commerce. The research ofSiGe technology starts a little later in our country and is mostly developed in university, whichjust pay their attention on the theoretical research, the development of SiGe products advancedslowly by limited process conditions. Therefore, we choose the low cost SiGe HBT withAPCVD epitaxy and SiGe low noise amplifier as research object, we use the0.6μm Si processesline of the13thresearch Institute of China Electronics Technology Group Coporation as ourexperimental platform to develope practical SiGe products, the main research contents in thisdissertation are as follows:1) Models of SiGe physical parameter are summarized, emitter junction current injectionration, the hole reversed injection current in base, neutral base region recombination,space-charge region SRH recombination and space-charge region Augre recombination areanalysized, on the base of which the model of AC parameter and DC parameter are analyzed.2) According to requirement of electrical parameters of SiGe HBT, the hetero emitterjunction structure and practical process conditions, lateral and vertical structure parameters ofSiGe HBT are optimized, based on which characteristic frequency and the maximum current gain are expected, fT=16.9GHz, β=103.3) APCVD SiGe epitaxy technique, emission mesa self-ceasing etching technique, N typedoping poly silicon and annealing technique, and metal silicide fabricating technique are realizedsuccessfully, a set of processing technology of poly silicon emission mesa SiGe HBT isdeveloped, the test results show that the maximum DC current gain is70, its V_BEFis0.85V atIB=25mA, BV_CBOis up to25V, fT=11.2GHz, its Noise Fingure is1.54dB and GPis13.86dB atf=1GHz.4) The SiGe HBT package is represented by equivalent circuit and S parameter of the chipextraction is realized by Microwave Office.5) A low noise amplifiers using two stage cascade topology is designed, SiGe HBT as theactive device is used in the circuit. The contradiction between gain flatness in the wholebandwidth and the noise performance of circuit is solved by shunt capacitance at the emitter,simulation results show that its gain S21≥20dB, gain flatness is controlled in1dB, NoiseFigure≤2.5dB and the stability factor≥1in the whole0～2GHz frequencies.