1. NanoFab Simulator Update
Nick Reeder, May 4, 2012

2. Updates to Thermal Oxidize Code
Oxidizes existing material instead of depositing a new layer on top.
Assumptions:
Si becomes SiO2.
All metals are oxidized, and subsequently can’t be etched.
Other materials (Ge and all dielectrics) are unaffected by oxidation.
Question:
When we oxidze doped Si, is the SiO2 still doped, and should we keep track of doping?

3. Updates to Expose Code
Photoresist on sidewalls is UV-exposed, as well as resist on top surfaces.
No UV-exposure takes place beneath regions of any non-photoresist material.
Problems:
Doesn’t correctly handle resist lying directly under other material and within the diffraction cone of a mask.
Profile of exposed region within resist is not correct. (Not modeling absorption.)

4. New Code: Implant
Lets user dope silicon or germanium as n, n+, p, or p+. Can later re-dope to a different depth or doping level.
Assumption:
No doping takes place beneath regions of any material other than Si or Ge.
Question:
Does doping diffuse horizontally within the Si, or is horizontal extent the same as window’s?

5. Other Known Problems
Spin coat: Resist adheres to underside of horizontal surfaces.
Sputter: Doesn’t model sputtering angle, and regions shaded by other structures are sputtered, but shouldn’t be.

6. Activity
Not started
Partial
Complete
Simulation coding
Clean X
Spin coat
Bake
Mask/Expose/Develop
Evaporate
Thermal oxidation
CVD
Sputter
Wet etch
Plasma etch
Lift off
Polish
Implant
Track time, cost, quality of each process
User -interface coding
History with option to revert
Save/open history files
Edit colors
User-defined materials
Profilometer
Producing embedded media (videos, photos, etc.)
Testing
Documentation