Double Avalanche Injection in Diode Avalanche Sharpeners

Picosecond-range avalanche sharpening diodes commutating fast-rising high-voltage pulses of submicrosecond duration are simulated numerically. It is demonstrated that the maximum duration of the commutated pulse are limited by physical phenomena related to the transition of the diode to the double-avalanche-injection mode instead of the drift extraction of nonequilibrium electron–hole plasma. Double avalanche injection is in principle capable of supporting the diode structure in the conducting state after switching. However, the negative differential conductivity, which is attributed to the double injection mode, causes the transverse instability of uniform current distribution and isothermal current filamentation.