Solid-state delayed breakdown picosecond closing switch based on a new profile of p(+)nn(+) silicon structure is demonstrated in this paper. Physical processes, which underlie the operating principle of high-power closing switch based on delayed breakdown diode (DBD), are discussed. From the results of numerical simulations by changing structure parameters and physical parameters, single device has demonstrated reliable operation at 2.3 KV, 89 ps risetime, and output voltage ramp of up to 30 KV/ns. As a contribution to the optimized design, the device parameters, which need to be improved in order to design better device, are discussed in detail. (C) 2004 Elsevier Ltd. All rights reserved.