Bulk semiconductor switch

Claim 1

Apparatus for switching kilovolt magnitude voltages in times of the order of one nanosecond or less, the apparatus comprising: a block of electrical insulating material; two microstrips of electrically conducting material of thickness 1-3 μm, collinearly positioned and spaced apart from one another by a gap of 1-3 mm, both microstrips being mounted on one side of the insulating material block; a substantially rectangular block of solid semiconductor material having a length of at least twice the length of the microstrip gap and being doped with boron at a concentration of between 10 15 /cm 3 and 10 18 /cm 3 , with the semiconductor block being maintained in electrical contact with the two microstrips and lying across the microstrip gap; a voltage source electrically connected to the two microstrips to impress a substantially constant voltage of at least 5 KV between the microstrips; cryogenic cooling means adjacent to the semiconductor block for cooling the block to a temperature T≦230° K.; and a source of pulsed radiation producing a radiative beam output of 10-100 nanojoules, the radiation beam being directed at the microstrip gap and the semiconductor block lying between the microstrip gap and the pulsed radiation source.