A compound semiconductor device disclosed herein includes a substrate, an electron transit layer formed on the substrate, a compound semiconductor layer containing gallium and formed on the electron transit layer, a diffusion preventing layer containing gallium oxide and formed on the compound semiconductor layer, an insulation layer formed on the diffusion preventing layer, and a source electrode, a drain electrode, and a gate electrode formed over the electron transit layer at a distance from one another.

pHEMT-based circuits and methods of improving the linearity thereof. One example pHEMT circuit includes a pHEMT connected between an input terminal and a load and a non-linear resistance connected to the pHEMT. The pHEMT produces a first harmonic signal at the load responsive to being driven by an input signal of a fundamental frequency received at the input terminal, the first harmonic signal having a first phase. The non-linear resistance has a resistance selected to produce a second harmonic signal at the load having a second phase opposite to the first phase. Methods can include determining a first amplitude and a first phase of a first harmonic signal produced at the load by a pHEMT in an ON state, and tuning the non-linear resistance to produce at the load a second harmonic signal having a second amplitude and a second phase that minimizes a net harmonic signal at the load.

An RF amplifier device includes a semiconductor die and an integrated passive device (IPD) on a ground flange. The IPD includes a semiconductor substrate and a metal-insulator-metal (MIM) capacitor coupled to the semiconductor substrate. The MIM capacitor includes a first electrode, a second electrode, and a dielectric between the first electrode and the second electrode. A first RF capacitor is over the semiconductor substrate and a second RF capacitor is over the semiconductor substrate. A metal layer is patterned to form a portion of an elevated metal shielding structure, a first plate of the first RF capacitor and a first plate of the second RF capacitor. The elevated metal shielding structure is over the MIM capacitor. The IPD is electrically coupled to the semiconductor die.

An output network connected to an output of a nonlinear unmatched power amplifier that provides an amplified voltage signal at a fundamental frequency. The output network includes multiple acoustic resonators configured to match multiple harmonic frequencies of the amplified voltage signal to one of substantially zero impedance, appearing as a short, or substantially infinite impedance, appearing as an open, resulting in zero voltage or zero current, respectively, to avoid power distribution at the higher harmonic frequencies. Each higher harmonic frequency is higher than a first harmonic frequency of the multiple harmonic frequencies, which is a fundamental frequency.

An output network connected to an output of a nonlinear unmatched power amplifier that provides an amplified voltage signal at a fundamental frequency. The output network includes multiple acoustic resonators configured to match multiple harmonic frequencies of the amplified voltage signal to one of substantially zero impedance, appearing as a short, or substantially infinite impedance, appearing as an open, resulting in zero voltage or zero current, respectively, to avoid power distribution at the higher harmonic frequencies. Each higher harmonic frequency is higher than a first harmonic frequency of the multiple harmonic frequencies, which is a fundamental frequency.

A switch element includes a source having a plurality of source fingers and a drain having a plurality of drain fingers interleaved with the source fingers. An active mesa region is defined between at least one of the plurality of source fingers and an adjacent at least one of the plurality of drain fingers. A plurality of gates are disposed between the at least one of the plurality of source fingers and the adjacent at least one of the plurality of drain fingers. At least one of gates extends into the active mesa region from outside of the active mesa region and terminates within the active mesa region.

An e-band transceiver includes a transmitter circuit and a receiver circuit. The transmitter circuit includes a surface mounted technology (SMT) module on which is mounted a silicon-germanium (SiGe) bipolar plus CMOS (BiCMOS) converter, a gallium arsenide (GaAs) pseudomorphic high-electron-mobility transistor (pHEMT) output amplifier coupled to the SiGe BiCMOS converter, and a microstrip/waveguide interface coupled to the GaAs pHEMT output amplifer. The receiver circuit of the e-band transceiver includes a receiver-side SMT module on which is mounted a receiver-side SiGe BiCMOS converter, a GaAs pHEMT low noise amplifier coupled to the receiver-side SiGe BiCMOS converter, and a receiver-side microstrip/waveguide interface coupled to the receiver-side GaAs pHEMT low noise amplifier.

A semiconductor device comprises a substrate and a high-electron-mobility transistor (HEMT). The substrate is formed with a recess. At least a portion of the HEMT is disposed in the recess. A method for manufacturing the semiconductor device is also disclosed. A radio frequency (RF) front-end module that employs the semiconductor device is also disclosed.

Power amplification system is disclosed. A power amplification system can include a Class-E push-pull amplifier including a transformer balun. The power amplification can further include a reactance compensation circuit coupled to the transformer balun. In some embodiments, the reactance compensation circuit is configured to reduce variation over frequency of a fundamental load impedance of the power amplification system.

Power amplification system is disclosed. A power amplification system can include a Class-E push-pull amplifier including a transformer balun. The power amplification can further include a reactance compensation circuit coupled to the transformer balun. In some embodiments, the reactance compensation circuit is configured to reduce variation over frequency of a fundamental load impedance of the power amplification system.