Semiconductor Switch Simulations Texas Tech U.

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Semiconductor Switch SimulationsTexas Tech U.
Sandia National Labs

• Goals
• Simulations Breakdown lock-on in
  photoconductive semiconductor switches (PCSSs)
• Understand the behavior of GaAs, Si, InP PCSSs
  at 4 to 30 kV/cm fields.
• Approach
• Collective impact ionization theory Effect of
  carrier-carrier scattering on impact ionization.
  
• Simulations Ensemble Monte Carlo Maxwellian
  distribution
• Results Generalized Breakdown
• Breakdown lock-on Two aspects of the same
  phenomenon
• Steady state electric field (F) carrier density
  dependence (n) of breakdown
• Personnel Ken Kambour, PhD student/Sandia
  visitor H.P. Hjalmarson (Sandia), C.W. Myles
  (TTU)

Fig. 1. Photoconductive switch (PCSS) with
optical illumination and current filaments
Fig. 2. Generalized Breakdown (Model Material) n
vs. F Minimum F on curve Breakdown field
without (red) with (blue) carrier-carrier (CC)
scattering. ? CC-scattering lowers the breakdown
field. Lock-on Breakdown with CC scattering.