Nanotech 2006 Vol. 3
Nanotech 2006 Vol. 3
Technical Proceedings of the 2006 NSTI Nanotechnology Conference and Trade Show, Volume 3

Compact Modeling Chapter 7

Analysis and Modeling of NQS Effects in MOSFET’s

Authors: Y. Ma, M-C Jeng, H. Liang and Z. Liu

Affilation: Cadence Design Systems, Inc., United States

Pages: 780 - 783

Keywords: NQS, MOSFET model, charge partition

Three issues regarding NQS effect in MOSFET’s are investigated: When NQS effect becomes significant, NQS effect on channel charge partition, and its implementation in advanced MOSFET models (PSP, Hisim2 and Bsim4).<br>Channel segmentation method [1] with N=10 is used in the investigation. Device is biased at strong inversion region with Vds=0. Small signal input is added to drain node and gate current is used as monitor. The starting point of NQS (5% degradation of the segmentation simulation compared with single device simulation) is found to be around 30% to 40% of device unit-gain frequency (ft), and the percentage is smaller for shorter devices. Simple model is developed to model the frenquency and channel length dependent of NQS starting point.<br>Drain charge is found to be around 35% of the total channel charge using segmentation simulation, while it is 44% for single device simulation without NQS effect, and around 42% for single device simulation with NQS effect using hisim2 model. This shows the difference from the 40/60 Ward-Dutton charge partition in QS mode.<br>Three NQS implementations are compared: internal node approach (Bsim), hidden state approach (Hisim) and Spline corelation approach (PSP). First two are theoretically equivalent. Non-ideal behavior are observed in the latter two and analized in this work.<br>&nbsp;<br><br>Ref:<br>[1] A.J. Scholten, L.F. Tiemeijer, P.W.H. de Vreede and D.B.M. Klaassen, Tech. Dig. International Electron Device Meeting, 1999, p163

Analysis and Modeling of NQS Effects in MOSFET’s

ISBN: 0-9767985-8-1
Pages: 913
Hardcopy: $119.95