Optimum transit angles of millimeter-wave Si IMPATT diodes
Optimum transit angles for maximum output power in the millimeter-wave IMPATT diodes are calculated analytically by considering the carrier diffusion process through the space-charge region. It is found that the optimum transit angle decreases, as the space-charge layer width reduces. The theoretical results show satisfactory agreement with the previously published experimental results for Si p+-n-n+abrupt junction diodes.
CW millimeter-wave IMPATT diodes with nearly abrupt junctions
Output powers of 23 to 150 mW were obtained from silicon avalanche diodes with a nearly abrupt junction in the 50- to 84-GHz range in continuous operation. The maximum efficiency was about 3 percent.
Microwave Si avalanche diode with nearly-abrupt-type junction
Microwave Si avalanche diodes with a nearly-abupt-type junction have been made. The maximum output power so far obtained in CW operation is 1.1 watts at 12 GHz with an efficiency of 7.7 percent. The maximum efficiency observed is 8.0 percent. The improved performance over the previously reported p \nu n structure, for which the best result was 250 mW at 12 GHz with an efficiency of 2.8 percent results from a reduction in length of the avalanche region in the abrupt junction. In the previously reported p \nu n diode the efficiency is still sharply increasing at the burnout point, while in the present diode the efficiency is nearly saturated at the burn-out point. The advantages and disadvantages of using different polarity of the diode (p on n or n on p) and different material (Ge) are given. Small-signal theory was used to analyze device operation.