N-polar GaN Cap MISHEMT with record 6.7 W/mm at 94 GHz

摘要: The high critical electric fields and large charge densities associated with III-N based electron mobility transistors (HEMTs) make this technology an attractive candidate for solid state power amplification at W-band. To date, reports on W-band GaN HEMTs MMICs have primarily featured devices fabricated in the Ga-polar orientation [1, 2]. In work, advantages of N-polar are exploited to produce a MISHEMT exhibiting record 6.7 W/mm peak output (Pout) 94 GHz. key component device design is situ epitaxial passivation layer access regions device. combination inherent polarization N-polar, cap acts both eliminate surface dispersion improve conductivity transistor. results presented here build upon work reported [3] [4] by transitioning from sapphire SiC substrate reduce self-heating. This has resulted over 2x increase density compared [4].