proposed that in some cases, the off-state leakage current is likely to be dominated by the surface leakage current through the electrode pad on the etched GaN buffer. 7 The damage caused by a traditional invasive device isolation process, such as mesa etching and ion implantation, is a critical leakage path. 1–6 While the geometrical size of the device shrinks, thus resulting in higher integration density, the off-state leakage current has become increasingly crucial for both discrete high electron mobility transistors (HEMTs) and a monolithic microwave integrated circuit (MMIC). GaN electronics have emerged as a crucial technology for energy and communication industries due to their high breakdown voltage, fast switching speed, and high temperature (HT) operation capability. This work demonstrates that polarization isolation is a promising alternative toward the plasma-damage-free isolation for GaN electronics. Moreover, the PI-HEMT device shows a low off-state leakage current of 2 × 10 −8 mA/mm with a high I on/I off ratio of 10 9 and a nearly ideal subthreshold slope of 61 mV/dec. Aside from that, a high isolation breakdown voltage of 2628 V is demonstrated for the PI-HEMT structure with 3 μm isolation spacing, which is two-times higher than a conventional mesa-isolation HEMT. Structures of polarization-isolated high electron mobility transistors (PI-HEMTs) exhibit significantly reduced isolation leakage currents by up to nearly two orders of magnitude at 50 V voltage bias compared to the state-of-the-art results.

The two-dimensional electron gas (2DEG) was formed at III-polar regions but completely depleted in N-polar regions, thereby isolating the 2DEG channels with a large 3.5 eV barrier.

Specifically, adjacent III- and N-polar AlGaN/GaN heterojunctions were grown simultaneously on the patterned AlN nucleation layer on c-plane sapphire substrates. In this study, we propose a new paradigm of polarization isolation utilizing intrinsic electronic properties, realizing in situ isolation during device epitaxy without the need of post-growth processing.

GaN electronics have hinged on invasive isolation such as mesa etching and ion implantation to define device geometry, which, however, suffer from damages, hence potential leakage paths.

Download hemt for free