Title :
RF linearity study of SiGe HBTs for low power RFIC design. I
Author :
Yuan, Xiaojuen ; Lie, D.Y.C. ; Larson, L.E. ; Blonski, J. ; Gross, J. ; Kumar, M. ; Mecke, J. ; Senior, A. ; Chen, Y. ; Poh, Andrew ; Harame, David
Author_Institution :
Commun. Res. & Dev. Center, IBM Microelectron., San Diego, CA, USA
Abstract :
The RF linearity characteristics of a 0.2 μm/120 GHz fT silicon germanium (SiGe) heterojunction bipolar transistor (HBT) are analyzed using a simplified VBIC model. This model is verified using on-wafer two-tone tests. The study shows that the extrinsic emitter resistance, re, has a major impact on transistor linearity through negative feedback and feedback induced cancellation of the third-order intermodulation products generated by the exponential nonlinearity of the transconductance. The base-collector-junction capacitance also contributes to the distortion at high bias currents. The distortion introduced by the weak avalanche current at high collector voltages is also appreciable. The nonlinearity of the base-emitter capacitance (including junction capacitance and diffusion capacitance) and the base current have minimum impact on transistor linearity compared to the effects mentioned above for frequencies under 5 GHz.
Keywords :
Ge-Si alloys; UHF bipolar transistors; capacitance; equivalent circuits; feedback; heterojunction bipolar transistors; intermodulation distortion; low-power electronics; microwave bipolar transistors; radiofrequency integrated circuits; semiconductor device models; semiconductor device testing; semiconductor materials; 0.2 micron; 120 GHz; 5 GHz; RF linearity characteristics; RF linearity study; SiGe; SiGe HBTs; VBIC model; base-collector junction capacitance; base-emitter capacitance nonlinearity; diffusion capacitance; distortion; extrinsic emitter resistance; feedback induced cancellation; heterojunction bipolar transistor; high bias currents; high collector voltages; intermodulation products; low power RFIC design; negative feedback; on-wafer two-tone tests; third-order IMD products; transconductance exponential nonlinearity; transistor linearity; weak avalanche current; Capacitance; Germanium silicon alloys; Heterojunction bipolar transistors; Linearity; Negative feedback; Radio frequency; Radiofrequency integrated circuits; Silicon germanium; Testing; Transconductance;
Conference_Titel :
Microwave and Millimeter Wave Technology, 2002. Proceedings. ICMMT 2002. 2002 3rd International Conference on
Print_ISBN :
0-7803-7486-X
DOI :
10.1109/ICMMT.2002.1187637
