Biomedical and biochemical researchers analyse materials by observing the electrical interactions and resonances of specimens subjected to pulses of high frequency energy. It is desired to increase the sensitivity and resolution of pulsed magnetic resonance instrumentation. The use of higher power, higher speed pulses is limited by the capability of the switching devices used to produce energy pulses. By using arrays of switching diodes placed on a common semiconductor substrate, it is possible to provide useful switching performance at 140 GHz with powers about 10 times that of commercial devices. However, parasitic effects increase the effective switching time to the microsecond range. The goal of the proposed effort is to demonstrate the feasibility of fabricating high speed switching diodes, with a switching speed of a few nanoseconds, in a high power array structure. This involves 1) analyzing the parasitic effects which hamper previous diode structures, 2) creating innovative new geometries to minimize the problems, 3) selecting from the many contemporary three dimensional fabrication processes the one most practical for the device geometry, 4) fabricating test diodes and 5) testing them for switching functionality and speed.
There are presently several thousand electron magnetic resonance laboratories in universities, medical schools, industry and government. The availability of high speed, high power switches will allow a new generation of pulsed resonance instrumentation for applications in biomedicine, chemistry, environment and energy.
