Modelling, Analysis and Simulation Tunneling-assisted impact ionization fronts in semiconductors

We propose a novel type of ionization front in layered semi ondu tor stru tures. The propagation is due to the interplay of band-to-band tunneling and impa t ionization. Our numeri al simulations show that the front an be triggered when an extremely sharp voltage ramp ( 10 kV=ns ) is applied in reverse dire tion to a Si p n n stru ture that is onne ted in series with an external load. The triggering o urs after a delay of 0.7 to 0.8 ns. The maximal ele tri al eld at the front edge ex eeds 10 V= m. The front velo ity vf is 40 times faster than the saturated drift velo ity vs. The front passes through the n base with a thi kness of 100 m within approximately 30 ps, lling it with dense ele tron-hole plasma. This passage is a ompanied by a voltage drop from 8 kV to dozens of volts. In this way a voltage pulse with a ramp up to 500 kV=ns an be applied to the load. The possibility to form a kilovolt pulse with su h a voltage rise rate sets new frontiers in pulse power ele troni s. 2000 Mathemati s Subje t Classi ation: 35B99, 74H60