This article investigates the influence of benzocyclobutene (BCB) passivation on the irradiation response of InP-based high electron mobility transistors (HEMTs). An abnormal behavior is observed, in which the threshold voltage is initially shifted negatively and then positively with proton fluence. Severe transconductance collapse and an increased breakdown voltage are observed at high proton fluence. RF characteristics exhibit a more robust radiation resistance compared to the dc characteristics. By conducting TCAD simulation, two defects responsible for the degradation behavior of threshold voltage are identified: the process-related traps activated by irradiation (donor) in the barrier and the surface states directly induced by irradiation (acceptor) on the gate-recess. Additionally, the effectiveness of BCB passivation in mitigating device degradation is demonstrated, resulting in a more stable threshold voltage and cutoff frequency. This improvement can be attributed to the reduced introduction rate of surface states on the gate-recess. This study provides valuable insights into the effects of proton irradiation on InP-based HEMTs and highlights the potential of BCB passivation for improving their radiation resistance.

In this article, a novel waveguide reconfigurable Schottky diode-based frequency doubler with tunable multiband high efficiency output is proposed and demonstrated. The multiband frequency output is achieved by reconfigurable input waveguide matching and cross-band output circuits matching. In the doubler, the whole cavity is composed of two parts: reconfigurable input matching waveguide cavities and coused main circuit associated with the coused cavity. These reconfigurable cavities are designed to match input impedance for corresponding band. The coused main circuit is adopted by weight optimization to fulfill output match of multiband. Then, the reconfigurable cavity is assembled into doubler through reduced-height waveguide choke flange, which aims to alleviate the assembly interconnection losses. Sample of the frequency doubler, operating at 170, 183, and 220 GHz, has been demonstrated based on this prototype. Measured results indicate that, the peak efficiencies of three bands are 38%, 34.5%, and 22.3%, respectively, with a total tunable operating bandwidth of 50 GHz.

In this letter, we present a novel analysis and design approach of self-oscillation frequency (SOF) for 0.8 μm InP DHBT ECL and CML static frequency dividers. SOF of ECL and CML dividers is designed to be the maximum value after theoretical analysis and multi-parameter optimization. The results show that the SOF of ECL and CML divider is 62 GHz and 37.5 GHz, respectively. With sinusoidal waveform input, the operating frequency range of ECL divider is from 0.1 GHz to 65 GHz, and CML is from 0.1 GHz to 55 GHz, while the cut-off frequency fT is 150 GHz. For ECL, the fT utilization of SOF (SOF/fT) is 0.413, and CML is 0.25. These are the maximum SOF results that can be designed for the two dividers under the same design conditions.

DC performances of a depletion-mode 100-nm In _0.53 Ga _0.47 As/InP composite channel InP-based high-electron-mobility transistor (HEMT) is investigated by using numerical simulation. The transfer, output, and breakdown characteristics of different doped InP subchannel thickness In _0.53 Ga _0.47 As/InP composite channel HEMT are compared. Decreasing the thickness of the doped InP subchannel from 10 to 5 nm results in a decline of the output current. However, the threshold voltage is increased from −0.77 to −0.6 V and the breakdown voltage is improved from 1.99 to 5.69 V at bias of ${V}_{{\mathrm {gs}}}-{V}_{{\mathrm {t}}} = -0.5$ V. To enhance the breakdown characteristic of In _0.53 Ga _0.47 As/InP composite channel HEMT, we minimize the thickness of the doped InP layer and replace the doped InP layer with the delta-doped layer. The structure is compared with the conventional double delta-doped structure in the performance of transfer, output, and breakdown characteristics. At ON-state, the electrons of two kinds of structure concentrate in the InGaAs channel. The output current and the threshold voltage of the composite channel structure are at the same level compared with the conventional double delta-doped structure. However, at OFF-state, because of the transfer of electrons into the InP subchannel, part of electric potential will not be concentrated at the drain side of the gate region but distributed in other area of the channel. A higher drain voltage is required to achieve electric field strength enough to breakdown and the breakdown voltage is improved obviously.

In this letter, we present a 25-GSa/s wideband track and hold amplifier using 0.8 μm InP process for high-speed analog sampling front-end. In this design, an active peaking input buffer is first used in the base-collector switching diode sampler. Moreover, it is carefully calculated and analyzed. The dominant pole in the signal path of the circuit is canceled by one zero produced by the active peaking structure, therefore, the bandwidth is extended. The experimental results show that a total harmonic distortion (THD) of less than -27 dBc and spurious-free dynamic range (SFDR) of better than 32.5 dB are demonstrated at a 25-GSa/s sampling rate. In hold mode, the isolation is better than -42 dB. In addition, it has an 0.156–fT bandwidth from DC to 25 GHz within 160 GHz fT, which is a very competitive value compared with other reported THAs using InP process.

In this letter, a high-speed wideband track-and-hold amplifier (THA) is implemented in a 0.8 μm InP double-heterojunction bipolar transistor (DHBT) process. This THA is based on a base-collector (b-c) switching diode architecture and achieves a -3 dB bandwidth of 35 GHz at a sampling rate of 30 GSa/s. For the first time, an enhanced unity-gain frequency (fT) doubler and an active peaking technique are used together in the design of the b-c switching diode sampler. The dominant pole of the THA is canceled by one zero produced by the active peaking structure. This is one step to improve the bandwidth. Secondly, the enhanced fT-doubler structure improves the driving capability of the input buffer at high frequencies. Therefore, the bandwidth of the THA is further extended. The measurement results show a total harmonic distortion (THD) of <-30.0 dBc and a maximum spurious-free dynamic range (SFDR) of 47.07 dB at a 30-GSa/s sampling rate. S-parameter tests show a better than -43 dB isolation within 45 GHz in hold-mode, and a -3 dB bandwidth of 35 GHz in track-mode under a 165 GHz device fT. The proposed THA has the potential for high-speed broadband applications due to its competitive performance.