Tunneling-assisted IMPATT operation

The influence of tunneling on the efficiency of millimeter-wave IMPATT diodes is investigated. For a reliable estimation of this influence, the tunnel generation rate coefficients are measured from silicon p-i-n diodes. The Read equation is solved taking a time-dependent tunnel current into account. The phase distortion, which is responsible for the efficiency degradation caused by tunneling, is calculated analytically and numerically. It is shown that for an exact solution the injected current density should be calculated numerically. The results suggest that for efficient silicon IMPATT diode operation, the maximum electric field should be below 1*10/sup 6/ V/cm. Due to the current and field dependent representation of the injection phase, there are direct consequences on the design of millimeter- and submillimeter-wave transit time diodes for high power generation as well as for low-noise operation.<
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