Modeling and analysis of non-rectangular gate for post-lithography circuit simulation

Ritu Singhal, Asha Balijepalli, Anupama Subramaniam, Frank Liu, Sani Nassif, Yu Cao

Research output: Chapter in Book/Report/Conference proceedingConference contribution

51 Scopus citations


In the nano regime it has become increasingly important to consider the impact of non-rectangular gate (NRG) shape caused due to sub-wavelength lithography. NRG dramatically increases the leakage current and requires geometry dependent transistor models for post-litho circuit simulation. In this paper, we propose a coherent modeling approach for non-rectangular gates based on equivalent gate length (L e). A gate-voltage dependent model of L e is developed which is scalable with design conditions, continuous across weak and strong inversion regions, accurate for both leakage and saturation current, and compatible with standard circuit analysis tools. We systematically verify this approach with 65nm TCAD simulations. A generic CAD algorithm is further proposed to predict the value of L e under various non-rectangular geometries. The interaction with the narrow-width effect is efficiently convolved in this method. Depending on the gate geometry, the leakage current can vary more than 15X at 65nm technology node. Our analytical method well captures this effect. Finally, we extrapolate the impact of NRG effect on future technology generations. The proposed model can be easily extracted from TCAD tools or direct silicon data. It bridges the gap between lithography, simulation, and circuit analysis for measuring transistor performance under increasingly severe NRG effect.

Original languageEnglish (US)
Title of host publication2007 44th ACM/IEEE Design Automation Conference, DAC'07
Number of pages6
StatePublished - 2007
Event2007 44th ACM/IEEE Design Automation Conference, DAC'07 - San Diego, CA, United States
Duration: Jun 4 2007Jun 8 2007

Publication series

NameProceedings - Design Automation Conference
ISSN (Print)0738-100X


Other2007 44th ACM/IEEE Design Automation Conference, DAC'07
Country/TerritoryUnited States
CitySan Diego, CA


  • Compact modeling
  • Equivalent gate length
  • Leakage
  • Narrow-width effect
  • Non-rectangular gate

ASJC Scopus subject areas

  • Hardware and Architecture
  • Control and Systems Engineering


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