FinFET Mismatch in Subthreshold Region: Theory and Experiments

• Published in: IEEE transactions on electron devices 2010-11, Vol.57 (11), p.2848-2856
• Main Authors: Magnone, Paolo, Crupi, Felice, Mercha, Abdelkarim, Andricciola, Pietro, Tuinhout, Hans, Lander, Robert J P
• Format: Article
• Language: English
• Subjects: Applied sciences; Channels; Correlation; Devices; Dielectrics; Electric potential; Electronics; Exact sciences and technology; Field programmable gate arrays; FinFET; FinFETs; Fluctuation; Gates; line edge roughness (LER); mismatch; modeling; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Silicon; subthreshold swing; Swing; Theory; Threshold voltage; Transistors; variability; Voltage
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/TED.2010.2068430

In this paper, we study the drain-current mismatch of FinFETs in subthreshold, from both modeling and experimental point of view. We propose a simple model that takes into account the effect of threshold voltage and subthreshold swing fluctuations and their correlation. For long-channel devices (longer than a critical length LC ), characterized by a subthreshold swing close to the ideal value, the overall current mismatch is dominated by threshold voltage fluctuations and, therefore, is gate voltage independent. The subthreshold swing fluctuations give a negligible effect on the drain-current mismatch and are uncorrelated with the threshold voltage fluctuations. For short-channel devices (shorter than a critical length LC ), characterized by a strong dependence of subthreshold swing on the channel length, the overall current mismatch presents an additional relevant contribution associated with the subthreshold swing fluctuations. This component depends on the gate voltage overdrive and is ascribed to the gate line edge roughness, resulting in a partial correlation between threshold voltage and subthreshold swing fluctuations.