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Background

A Semiconductor Opening Switch (SOS) is a high-power pulse diode designed to interrupt currents at density levels of up to 10 kA/cm2 in less than 10 nanoseconds.  Current state of the art SOSs are widely used as solid-state generators to produce high power laser light, x-rays, and neutron pulses.  One of their drawbacks however is that their performance is compromised by the presence of pre-pulses.  These unwanted pulses feature long duration time and slow rise time, which degrades the voltage pulse rise time, peak voltage, etc. of the SOS device.  There is a need for a different SOS device structure that is able to suppress or eliminate these pre-pulses.

Description

LLNL developed a novel SOS diode structure starting with a n-type silicon wafer.  On the appropriate sides of the wafer, donor and acceptor dopants with specifically designed and optimized concentration profiles are diffused in the structure.  Crucially, an extra n-region is introduced to the structure to address pre-pulses.  The result is a SOS diode with an optimized p+/p/n-base/n+ structure, and an extra layer that has a gradient n-doping.  The incorporation of this layer effectively suppresses the pre-pulses, increases peak voltage and reduces pulse rise time.  This approach has been validated in optimization simulations.  

RELATED PUBLICATION:

https://ldrd-annual.llnl.gov/archives/ldrd-annual-2023/project-highlights/directed-energy/gallium-arsenide-semiconductor-opening-switches-pulsed-power-systems

Image Caption: Schematic of the SOS switching circuit

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Advantages
  • Value Proposition:  Improved performance of SOS diodes
  • Vital for compact high voltage pulse generators
Potential Applications
  • Pulsed-power physics
  • Compact high voltage pulse generators
  • High power electronics
Development Status

Current stage of technology development: TRL ☐ 0-2      3-5     ☐ 5-9 

LLNL has filed for patent protection on this invention.

Reference Number
IL-13828
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