MURI Kickoff Meeting

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MURI Kick-off Meeting

• Prof. Mark E. Law
• Department of Electrical and Computer Eng.

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FLOOPS / FLOODS

• Object-oriented codes
• Multi-dimensional
• P Process / D Device 90 code shared
• Scripting capability for PDEs - Alagator
• Commercialized - ISE / Synopsis
• Licensed at approximately 200 sites world-wide

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Object Oriented

• Modular - Grid / Operators / Fields
• Code written for elements works in all dimensions
• Example - every element can compute Size

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Example - Refinement

• Local Error Estimate - Bank Weiser Based
• Remove
• Replace an edge w/ a node
• Dose Stays Constant
• Position new node at optimal quality position
• Addition
• Subdivide an edge
• Find effected volumes (Voronoi)
• Centroidal positioning

SRC Supported
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Anisotropic Grid - Initial

• Rectangular region created at the command line
• Remainder of the silicon is smoothed
• Silicon Elements 478
• Joint Quality 0.936
• Average Quality 0.944

SRC Supported
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Anisotropic Grid

• Refinement of both extension and deep source /
  drain
• LevelSet Spacer
• Note - etch onto rectangular regions
• Silicon Elements 1150
• Joint Quality 0.937
• Average Quality 0.961
• Improved Quality on Add!

SRC Supported
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Anisotropic Grid - Final Anneal

• Refinement and unrefinement have occurred
• Refinement under gate edge as extension diffuses
• Silicon Elements 1056
• Joint Quality 0.925
• Average Quality 0.957

SRC Supported
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LevelSet Example - 3D

• 3D Spacer Formation
• More robust - exploit publicly available 3D grid
  codes

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What is Alagator?

• Scripting language for PDEs
• Parsed into an expression tree
• Assembled using FV / FE techniques
• Stored in hierarchical parameter data base

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What is Alagator?

• Example use of operators for diffusion equation
• Ficks Second Law of Diffusion
• ddt(Boron) - 9.0e-16 grad(Boron)
• ?C(x,t) / ?t D ?2C(x,t) / ?x2

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Todays Transistor
Scaled MOSFETS and alternate materials to extend
Moores Law
S. Thompson et al., IEEE EDL. 191-193, 2004.

• Technology scaling is driven by cost per
  transistor
• Channel length scaling is slowing in bulk planar
  devices
• Limited by leakage current
• Strained Si devices

S. Thompson et al., IEDM Tech. Dig. 61-64, 2003.
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Finite Element Method Mechanics

• Theory of Elasticity linear elastic materials
• - Silicon is modeled as an isotropic material
  for simplicity
• Enhanced Alagator
• Added elastic operator for displacement
• Added source term operators
• Elastic(displacement) BodyStrain(Boronk)

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Stress Contours
MPa
Source FLOOPS
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Basic Upgrades

• FLOODS has been used for
• Bipolar devices (SiGe)
• GaN based heterostructures MEMs
• Noise simulations for RF devices
• Enhancements for modern MOS
• More flexible contacting options
• Account for quantum confinement
• Accurate mobility - transverse field

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Strain and SEU Upgrades

• Anisotropic operators
• Current direction, strain interaction
• Mobility has an orientation
• Density of States
• Recombination
• Driving Forces?

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SEU Enhancements

• Coupled to GEANT for charge cloud
• Investigate regrid / transient
• Circuit elements
• 3D Optimizations
• Memory cheap design
• Parallel Assembly / Factorization

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Summary

• Flexible tool with many appropriate capabilities
• Specific Radiation related enhancements will be
  performed
• Couple tool to others for system simulation