Performance Analysis And Modelling And Simulation Of SiGeC HBT

This thesis introduces the characters of SiGeC material and device, the advantages comparing with SiGe device andⅢ-Ⅴcompound semiconductor device, the energy band structure of SiGeC HBT and the effect of which by introducing Ge and C into the base region of HBT. This thesis also introduces the development status and application field.This thesis presents the difference between SiGeC HBT's and Si BJT's and SiGe HBT's DC and AC characters, and introduces the basic concepts of high frequency high power SiGeC HBT.A closed-form physical model of bse transit time considering the temperature effect of the electron is obtained. The comparison of the two models indicates the closed-form physical model is more accurate for ultra thin base SiGeC HBT.For ultra thin base SiGeC HBT, the base width is almost equal to the carrier mean free length, quasi-ballistic transport occurs when carriers cross the region in which only a few collisions take place. The velocity of the carriers may be much higher than the saturation velocity. Velocity overshoot occurs.This thesis also presents a general overview of process simulation model ATHENA and device simulation model ATLAS from SILVACO. An example of process simulation and device simulation is presented. Another simulation proves the closed-form physical model more accurate than the drift-diffusion model for ultra thin base SiGeC HBT.The energy band structure of SiGeC HBT can be changed by introducing different proportion of Ge or C content. The bandgap narrowing of SiGeC HBT base can generate an accelerated electric field which can shorten the base transit time,all of which greatly improve the performance of SiGeC HBT. The SiGeC HBT's process is compatible with Si BJT's, so the cost is cutted comparing withⅢ-Ⅴcompound semiconductor device. SiGeC HBT will have a broad application prospects in the field of VLSI.