Suppression of drain conductance dispersion in InP-based HEMTs for broadband optical communication systems

Demonstrated InP-based HEMTs without drain conductance (g/sub d/) frequency dispersion for broadband optical communication systems. It was possible to markedly suppress the g/sub d/ dispersion by using composite channel and double-doped structures rather than a conventional HEMT structure. Furthermore, we clarified that hole generation time by impact ionization determines the frequency range of the g/sub d/ dispersion in a conventional InP-based HEMT by investigating the g/sub d/ dispersion over a wide range of frequencies (100 Hz-20 GHz).