20-GHz high-power GaAs DDR-IMPATT diodes with a p+-p-n-n+structure

GaAs DDR (double-drift-region)-IMPATT diodes have been made by using epitaxial wafers with a p⁺-p-n-n⁺structure, which was made by successive liquid-phase epitaxy of p⁺, p, and n layers on n⁺substrate in one heat cycle. On the diodes with copper heat sink, the maximum CW output power of 1.2 W was obtained at 21 GHz with the efficiency of 15.6 percent.