We analyze the channel and surface charge dynamics of a high voltage AlGaN/GaN Heterostructure Field Effect Transistor (HFET) operating as a power switch. We demonstrate that operation in the voltage range exceeding 100V without field plates involves alternating of the surface compensating charge in the gate–drain spacing. Developed model predicts the switching speed limitation of power HFET determined by the surface recharge rate and provides new, voltage-scalable design approach of AlGaN/GaN power devices.

Analysis methodology for the charge pumping (CP) data, which considers non-elastic electron/hole capturing and releasing processes, is proposed. It is shown that the multi-phonon-assisted rearrangement of the dielectric lattice around the traps, associated with the charge trapping, is important for the interpretation of experimental results and needs to be taken into account. Analysis of the temperature dependent multi-frequency charge pumping data, measured on the MOSFETs with different thickness of the interfacial layer in the high-k dielectric gate stack, allowed to extract the trap energy and spatial profiles and helps to identify the nature of these traps.

We report on the first metal-oxide-semiconductor AlGaN/GaN radio-frequency (RF) switch with capacitively coupled contacts using a HfO 2 layer as the gate dielectric and surface passivation layer. The new insulating-gate RF switch has a lower leakage current and can handle higher RF powers than AlGaN/GaN HFET switches.

We report on the first metal-oxide-semiconductor AlGaN/GaN radio-frequency (RF) switch with capacitively coupled contacts using a HfO2 layer as the gate dielectric and surface passivation layer. The new insulating-gate RF switch has a lower leakage current and can handle higher RF powers than AlGaN/GaN HFET switches.

We propose a high-frequency extension of the transmission line model method that allows for independent extraction of open-surface sheet resistance of a semiconductor layer and that under metallization. The method is applied for the characterization of an AlGaN/GaN heterostructure with a high ( ~40%) Al content with and without a top dielectric layer. In both cases, the sheet resistance under the metal is approximately 30% smaller than that under the open surface. This reduction is attributed to the surface charge compensation by the top metal.

The cryogenic operation of a low-loss RF switch using a AlGaN/GaN metal-oxide semiconductor heterostructure field effect transistor is reported. At 77K the channel resistance of the MOSHFET is three times lower and the contact resistance is 20% lower compared to room temperature. As a result, the performance of the MOSHFET RF switch at 77K is even superior to that at room temperature.

We present the analysis and the performance characteristics of novel III-Nitride multigate (MG) radio-frequency (RF) switches fabricated over AlGaN/GaN heterostructures using capacitively coupled contacts (C-3). C-3 device technology does not require contact annealing and, thus, allows for fully self-aligned processing of MG devices with tight electrode spacing. The combination of C-3 electrodes with MG RF switch design results in devices with significantly lower OFF-state capacitance, higher isolation, and higher RF switching power as compared to conventional FET-based RF switches.