Research On Parameter Extraction And Modeling For RF/Microwave SiGe HBT

With the rapid growth of wireless communication, the device feature size continues to decrease. The transit frequencies for SiGe heterojunction bipolar transistors have been up to375GHz. As higher integration level, lower cost than III-V devices, SiGe HBT quickly becomes popular in mobile communication systems.For improving integrated circuit design yield, reducing the design cycle time and the time to market in the CAD-based design flow, validated and accurate SiGe HBT models are needed properly to be implemented in the design tools. With longer development cycle, poor accuracy for the universal application of the SiGe HBT model, more effort is needed to pay for the RF SiGe HBT model to meet most of the IC design requirements. The parameter extraction and modeling of SiGe HBT is studied im this paper. Based on this research topic, the following research results achieved have been listed as following:1) An improved small-signal equivalent-circuit model for silicon-germanium heteroj unction bipolar transistors is proposed. The proposed model has taken into account the effects of the base and collector metallisations. The prsented transistor model takes into account the parasitic effects such as substrate effect and the extrinsic capacitances. A semianalytical parameter-extraction procedure is proposed for the SiGe HBT small-singal modeling. The proposed modeling approach and parameter-extraction method are validated by SiGe HBT with0.2x5.9μm2emitter area up to40GHz.2) An improved large-signal equivalent-circuit model for SiGe HBT based on the MEXTRAM model (level504.5) is proposed. The proposed model has taken into account the soft knee effect. The accuray for DC performance of the proposed model is improved. The model has been implemented into the ADS circuit simulator using Verilog-A program. 3) A scalable large-signal model for SiGe heterojunction bipolar transistors is presented. Compared with GP model, the proposed model has taken into account the self-heating effects and a new base-collector break-down description. An improved method for extracting thermal resistance is proposed. Compared with the conventional method, more accurate thermal resistance has been extracted by using the proposed approach. The proposed scalable model is verified by the SiGe HBT with emitter area of0.3x20.3,0.3x13.9,0.3x9.9and0.3x1.9μm2.4) Accurate de-embedding technique based on transmission line theory is presented and applied to on-wafer polysilicon resistors modeling. Compared with the conventional de-embedding methods, not only the top metal layer but also the under-layer metal parasitics are removed from the on-wafer passive devices. The proposed de-embedding technique is validated by polysilicon resistors with occupying areas of20x2um2.This work is supported in part by the Doctoral Post Graduate Academic New Artist of ECNU (grant no.2010025), the Open Research Program of State Key Laboratory of Millimeter Waves, Southeast University (grant no.K201002), the Key Project of Chinese Ministry of Education (grant no.210080) and National Natural Science Foundation of China (No.61176036).