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Shinichi HOSHI Takayuki IZUMI Tomoyuki OHSHIMA Masanori TSUNOTANI Tamotsu KIMURA
The reduction of the drain current for InGaAs/AlGaAs pseudomorphic high electron mobility transistors (PHEMTs) has been observed due to the RIE-damage induced under the gate region. However, it has been found that the drain current can be recovered after the gate-drain reverse current stress even at room temperature. The recovery rate of the drain current strongly depends on the gate-drain reverse current density. The activation energy of the recovery rate has been confirmed to decrease from 0.531 eV to 0.119 eV under the gate-drain reverse current stress. This phenomenon can be understood as a recombination enhanced defect reaction of holes generated by the avalanche breakdown. The non-radiative recombination of holes at the defect level is believed to enhance the recovery of the RIE-damage.
Makoto SHIKATA Akira NISHINO Ryoji SHIGEMASA Tamotsu KIMURA Takashi USHIKUBO
A decision circuit with a function of detecting the phase difference between input data and clock signal is presented. Direct coupled FET logic (DCFL) was used for basic gates. The circuit architecture was chosen to be suitable for DCFL. Novel circuit technologies were adopted to the phase detectors. In GaAs/AlGaAs pseudomorphic inverted HEMT's were used for fabrication. The decision circuit showed a wide phase margin of 288 degrees and small decision ambiguity of 27 mVpp up to 10 Gb/s. Linear and wide-range phase detection was achieved as well as an ability to compensate the variation of transition density, input bias and temperature.