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.
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.
Image Caption: Schematic of the SOS switching circuit
Current stage of technology development: TRL ☐ 0-2 ☒ 3-5 ☐ 5-9
LLNL has filed for patent protection on this invention.
- Value Proposition: Improved performance of SOS diodes
- Vital for compact high voltage pulse generators
- Pulsed-power physics
- Compact high voltage pulse generators
- High power electronics
