The DFM Of Ultrahigh SiGe HBT

With the fast developments of wireless communication technologies and mobile communication systems, the requirements to the characteristics of devices and circuits are higher and higher, which ulteriorly force people to explore new materials and devices with new structures, in order to satisfy the requirements of semiconductor industry in the future. In all the new devices, SiGe heterojunction bipolar transistor obviously outgoes Si BJT devices andⅢ-Ⅴcompound heterojunction devices because of its numerous excellences of high performances, high integration level, low costs and compatibility with Si technologies et.al. SiGe HBT devices have been widely used in many aspects, such as mobile communications, satellite communications, sensor and radar technologies, and have becomed one of the best active research hotspots.The paper first generalized the development history and actuality of SiGe HBT inside and outside of the country, put forward the study significance and applied values; discussed the characteristics of SiGe alloy material, simply introduced two widely used epitaxy growth technologies——Ultrahigh Vacuum/Chemical Vapor Deposition(UHV/CVD) and Molecular Beam Epitaxy(MBE); detailedly analyzed the basic working principle and performances of SiGe HBT, including working currents, current gain, characteristic frequency and maximal oscillatory frequency, and presented corresponding count expressions, it emphasized the influences of all factors to characteristic frequency by analyzing the delay time of emitter, the memory time of emitter field, the transport time of base, the transport time of space charge field of collector, the delay time of collector respectively; it ascertained the correlative technologies used in device design, the reference targets of structure size and process parameters, according to the theoretical study and analysis, design rules and requirements of emitter, base and collector, it aimed at improving the current gain, frequency characteristics and punchthrough voltage; simply introduced the new generation TCAD simulation tools used in ultrahigh frequency SiGe HBT design, including process simulation tool-Sentaurus Process, mesh optimization tool- Sentaurus Structure Editor, device simulation tool-Sentaurus Device, resultsanalysis tools-Inspect and Tecplot SV, integrated design platform-SentaurusWorkBench; finally, it carried out the process simulation and device simulation of ultrahigh frequency SiGe HBT using Sentaurus TCAD simulation tools. It selected the base width, the base doping, the base Ge content, the emitter doping and the collector doping as control factors, based on the appropriate DoE methods and theories, set up reasonable RSM, studied how these process parameters affect the device physical charateristics and obtained the optimal process parameters values by optimizing design. Finally, the paper briefly analyzed and discussed the simulation results, it emphasized the gain charateristics, frequency characteristics and punchthrough characteristics of the device, and finally accomplished the DFM of ultrahigh frequency SiGe HBT, which has good performances and satisfies the ultrahigh frequency application field.The paper lucubrated in the process and device characteristics of ultrahigh SiGe HBT. The highest current gain of the SiGe HBT device accomplished here is 265, its characteristic frequency is 76GHz and maximal oscillatory frequency is 176GHz, the collector-base punchthrough voltage is 9.1V, the collector-emitter punchthrough voltage is 6V, the emitter-collector punchthrough voltage is 11V and the Early voltage is 18.35V. It is obvious that the gain characteristics, the frequency characteristics and the punchthrough characteristics all reached perfect design values. It established base to the more studies in SiGe HBT heterojunction devices and integrated circuits in the country, and possesses reference value and applied value. the which.