Backward diodes as microwave detectors

This paper examines the potential of pulse-bonded germanium backward diodes as microwave detectors. Use is made of I/V relationships derived from both theoretical considerations and measurements on larger area alloyed diodes, in estimating the l.f. short-circuit current sensitivity in the unbiased state, from which it is deduced that the signal/noise performance (tangential sensitivity) at Xband should be superior to that of conventional silicon detector crystals. The manufacture of point-contact backward diodes in a CV7180type cartridge is investigated with a range of materials and processes. Expected sensitivities at Xband are of the order 57dbm for diodes of 1k¿ video resistance, and this figure has been achieved with some samples. Some incidental properties are also discussed, such as flicker noise and burnout.