In this letter, a thin-barrier AlGaN/GaN Schottky barrier diode (SBD) is proposed and implemented in a three-stage high-power RF limiter module. Benefited from the thin-barrier epitaxy, a recess-free process in the Schottky region is allowed to avoid the plasma damage, resulting in low on-resistance of 5 $\Omega $ and high withstand voltage characteristics. In addition, the proposed SBDs have achieved a low junction capacitance of 0.35 pF at 0 V bias and a turn-on voltage of 0.5 V. With the optimized SBD and well-designed matching circuits, the limiter has reached a high power capacity of over 10 W in continuous wave (CW), 20 W in pulse mode, and a fast recovery time of 30 ns at a frequency of 3.5 GHz, exhibiting better characteristics than traditional limiters. Both simulation and measured results agree with each other. It indicates that the AlGaN/GaN-based SBD is promising for high-power and high-frequency limiters.

In this article, we report a major breakthrough in the recovery performance of microwave high-power limiters achieved through the utilization of gallium nitride (GaN) Schottky barrier diode (SBD) monolithic microwave integrated circuit (MMIC) technology. Introducing SBD into the limiter design to substitute traditional p-i-n diode can reduce design difficulty by eliminating the consideration of minority carrier lifetime. The GaN SBD, featuring a thin AlGaN barrier epitaxial structure and recess-free process in the Schottky region, achieves a low turn-on voltage of 0.64 V, establishing the design freedom of the threshold for the limiter. Based on these advantages, a novel design approach, distinct from traditional p-i-n diode limiters, is proposed and experimentally validated. Additionally, the intrinsic parameters of GaN-SBD suitable for lateral heterojunction structures are developed, and a SPICE model that can be applied to RF simulation is extracted through carefully designed de-embedding patterns. Building upon this methodology, a GaN-SBD limiter is designed and manufactured, demonstrating high incident power above 50 W in the continuous wave (CW) mode, over 140 W in the pulse mode, an insertion loss (lL) of less than 1 dB at 8 GHz, and a fast recovery time of 39 ns. The proposed SBD limiter design methodology is perfectly validated, demonstrating the promising prospects of GaN SBD-based limiters in future high-power and fast-recovery applications.

In this letter, a multistage high-power RF limiter based on a thin-barrier AlGaN/GaN Schottky barrier diode (SBD) has been proposed and demonstrated in 2–6 GHz. By multifinger device layout design with increased total anode width, the on resistance of the diode reduces drastically and the maximum RF current can be increased, resulting in an increase of the power capacity of the limiter. In addition, benefiting from the thin-barrier epitaxial design and plasma-damage-free SBD device fabrication, the response time and recovery time of the limiter can be reduced, as well. By incorporating the fabricated devices with a well-designed matching circuit, the RF limiter obtains high incident power above 50 W in continuous wave (CW) mode, over 100 W in pulse mode, a fast recovery time of 35 ns, and spike leakage free at 4 GHz. The simulation and measurement results are well-agreed with each other. This demonstration shows that the GaN-SBD-based limiter is promising for future high-power and high-frequency applications.

In this work, we investigate the soft breakdown (BD) behavior in thin-barrier (TB) AlGaN/GaN Schottky barrier diode (SBD) with carbon-doped GaN buffer. The soft BD behavior is the result of the coupling of multiple mechanisms. In the off-state, the ionized carbon (C) acceptors make the electric field ( ${E}$ -field) crowd at the cathode and cause the impact ionization. Then, the holes generated by impact ionization compensate with the ionized C acceptors, thus suppressing ${E}$ -field crowding and preventing the further avalanche BD. The residual holes flow to and accumulate under the anode, which leads to a continuous increase in the Schottky ${E}$ -field and Schottky leakage, eventually causing the soft BD. Due to the tunneling effect, Schottky leakage is highly sensitive to the Schottky ${E}$ -field in TB structure, so the leakage rise rate during soft BD is abnormally high.

This letter describes efficient high-power rectifiers, using a cost-effective AlGaN/GaN Schottky barrier diode (SBD) with accurate extraction of large-signal parameters as the rectifying device. The thin-barrier (TB) recess-free GaN SBD exhibits a low turn-on voltage of 0.5 V, a low on-resistance of 6.2 $~\Omega $ , a low junction capacitance of 0.28 pF, and a high breakdown voltage of 66 V. A precise large-signal equivalent-circuit model is derived by elaborating the measured $I$ – $V$ , $C$ – $V$ data, and $S$ -parameters under different dc bias conditions. For model verification, two separate rectifiers working at 5.8 and 10 GHz are fabricated. The measured results indicate that, with 31-dBm input power, the maximum efficiencies of the two rectifiers are 78.9% and 76.6% at 5.8 and 10 GHz, respectively. The maximum power handling capability of each single SBD reaches 36 dBm. Owing to the low-cost high-performance GaN SBD with an accurate model, the high-power rectifiers exhibit the merits of compact size and high efficiency, indicating great potential for large-scale microwave power transfer (MPT) applications, such as space solar power systems (SSPS).

In this article, a scalable model of thin-barrier lateral heterojunction AlGaN/GaN Schottky barrier diode (SBD) for RF simulation is proposed. By comparing the measured and modeled S -parameters under multibias bias conditions, it is verified that the scaling rule dependent on the effective junction area of the device can better predict the performance of large-size devices in the frequency range of 0.1–20 GHz. In addition, the C-band limiter is successfully designed by using the scalable SBD model. The physical and simulated S -parameters have good consistency, which further verifies the accuracy of the model.