Small Signal Measurements of the Microwave Impedance of QWJITT Diodes

This paper presents a comparison between experimental and calculated small signal microwave impedance for several quantum well injection transit time (QWITT) diodes. The measured results are in good agreement with the calculations based on a simple physical device model. This model accounts for transport effects in the depletion layer outside a resonant tunneling diode. Based on the theoretical calculations, an equivalent circuit for the QWIIT diode can also be used, whose elements correspond to physical phenomena. Thus, the rf behavior of a resonant tunneling diode can be predicted based only on its physical structure and a measurement of the dc IV curve for the device.