The effect of optically enhanced leakage current on S-band TRAPATT diode oscillators

The effects on output power and frequency of oscillation are presented and compared with a theoretical, closed form model. In general, the power decreases gradually and the frequency increases rapidly with photocurrent at low levels, while the power decreases rapidly while teh frequency levels off a higher levels of photocurrent. These results, however, are found to be very dependent on the tuning of the TRAPATT device. The design and fabrication of unique top ring contact N(+)PP(+) silicon devices was made to permit optical excitation. The devices were mounted junction side up with the top metal contact having an optical window to allow the light to shine directly on the silicon surface, and thus generate photocurrent. The two-dimensonal effects inherent in this structure were found to be negligible from passive RF tests.