Performance evaluation of picosecond high-voltage power switches based on propagation of superfast impact ionization fronts in SiC structures

Abstract

We employ a simple analytical model of superfast impact ionization front in a reversely biased p+-n-n+ structure to evaluate the performance of prospective 4H-SiC closing switches based on propagation of ionization fronts. The model allows to relate the order of magnitude values of the front velocity and the electron-hole plasma concentration behind the front to the basic material and structural parameters. We show that high avalanche breakdown field and impact ionization rate of the wide-band-gap 4H-SiC lead to dramatic improvement of switching characteristics with respect to Si structures currently used in pulse power applications. The concentration of electron-hole plasma generated by the front passage is of the order of 1018 versus 1016cm−3 in Si. The velocity of ionization front in 4H-SiC is several times larger than in Si. Finally, we discuss possible triggering mechanisms for the ionization front in SiC.

The Driving Conditions for Obtaining Subnanosecond High-Voltage Pulses From a Silicon-Avalanche-Shaper Diode

“…We feel this paper is a valuable contribution toward designing new fast-closing switches that may include advanced semiconductor materials, such as SiC [16]. It may also impact the design of the driving circuit as in [21], which may include a fast opening-switch component [24].…”

“…Their calculation showed that a reverse sharp voltage ramp of ∼10 kV/ns will result in a voltage drop of ∼8 kV within 15 ps, thus a voltage rise rate of ∼500 kV/ns can be applied to the load. A similar mechanism in a SiC p + -n-n + structure is calculated in [16]. Rodin et al [15] calculated that a voltage ramp of >1 kV/ns applied on a 100 μm Si bulk (without p-n junctions) can result in some 1-kV, 100-ps pulses [17].…”

Picosecond-Range Avalanche Switching of High-Voltage Diodes: Si Versus GaAs Structures

“…semiconductor material for high-voltage pulse power application [12], [13], have not been successful until now. The studies we report in this paper are part of the ongoing research project aimed at finding the physical fundamentals of delayed avalanche breakdown.…”

Computationally Assessing Diamond as an Ultrafast Pulse Shaper for High Power Ultrawide Band Radar

“…No reasonable semiconductor offers both improved breakdown field and high mobility and lifetime except for diamond and SiC to potentially outperform Si. The team at Ioffe is actively exploring the potential of the SiC technology [12][13][14] . Presented here is an early attempt to assess the potential of diamond.…”