Elimination of kink phenomena and drain current hysteresis in InP-based HEMTs with a direct ohmic structure

We eliminated kink phenomena and Ids hysteresis in a double-doped InP-based HEMT without degrading its frequency performance by fabricating direct ohmic contacts in the InGaAs channel. A direct ohmic structure lets us control current paths in the device and relax the electric field at the recess edge of the drain side. As a result, we can suppress impact ionization and decrease the hole currents that originate from the high electric field region at the recess edge of the drain side. Kink phenomena are eliminated in the direct ohmic structure. We also suggest a hole trap mechanism to explain the appearance of hysteresis in the I-V characteristic of the conventional nonalloyed ohmic structure device.