The generation of RF/microwave power is required not only in wireless communications, but also in applications such as jamming, imaging, RF heating, and miniature dc/dc converters. Each application has its own unique requirements for frequency, bandwidth, load, power, efficiency, linearity, and cost. RF power is generated by a wide variety of techniques, implementations, and active devices. Power amplifiers are incorporated into transmitters in a similarly wide variety of architectures, including linear, Kahn, envelope tracking, outphasing, and Doherty. Linearity can be improved through techniques such as feedback, feedforward, and predistortion.

No abstract

Charge-trapping defects in Pt/Al2O3/In0.53Ga0.47As metal-oxide-semiconductor capacitors and their passivation by hydrogen are investigated in samples with abrupt oxide/III-V interfaces. Tunneling of electrons into defect states (border traps) in the atomic layer deposited Al2O3 near the oxide/semiconductor interface is found to control the frequency dispersion of the capacitance in accumulation. Hydrogen anneals effectively passivate border traps in the oxide, in addition to some of the midgap states that control carrier generation in the channel. This is evident in the reduced frequency dispersion in accumulation, reduced capacitance-voltage stretch-out through depletion, and suppression of the inversion carrier response in capacitance-voltage measurements.

No abstract

No abstract