A perspective on multi-channel technology for the next-generation of GaN power devices

Abstract

The outstanding properties of Gallium Nitride (GaN) have enabled considerable improvements in the performance of power devices compared to traditional silicon technology, resulting in more efficient and highly compact power converters. GaN power technology has rapidly developed and is expected to gain a significant market share in an increasing number of applications in the coming years. However, despite the great progress, the performance of current GaN devices is still far from what the GaN material could potentially offer, and a significant reduction of the device on-resistance for a certain blocking voltage is needed. Conventional GaN high-electron-mobility-transistors are based on a single two-dimensional electron gas (2DEG) channel, whose trade-off between electron mobility and carrier density limits the minimum achievable sheet resistance. To overcome such limitations, GaN power devices including multiple, vertically stacked 2DEG channels have recently been proposed, showing much-reduced resistances and excellent voltage blocking capabilities for a wide range of voltage classes from 1 to 10 kV. Such devices resulted in unprecedented high-power figures of merit and exceeded the SiC material limit, unveiling the full potential of lateral GaN power devices. This Letter reviews the recent progress of GaN multi-channel power devices and explores the promising perspective of the multi-channel platform for future power devices.

Thermal management and packaging of wide and ultra-wide bandgap power devices: a review and perspective

“…GaN power HEMTs are commercially available in the voltage classes of 15-900 V [4,8] and have been recently demonstrated up to 10 kV [66] based on an emerging multichannel structure [67][68][69]112]. Thermal management is challenging for GaN HEMTs for two reasons.…”

Multidimensional device architectures for efficient power electronics

“…Multi-channel heterostructures reduce the sheet resistance (R SH ) by spreading a large 𝑛 into stacked channels with the 𝑛 in each channel not too high to compromise 𝜇 due to carrier scattering. The GaNbased multi-channel heterostructures can be either undoped [62][63][64][65] or doped, 36,43,66,67 and an R SH 3-10 times lower than the single-channel has been reported in both schemes. In an ideal undoped multi-channel, parallel 2DEGs and two-dimensional-hole gases (2DHGs) with equal 𝑛 are induced on the top and bottom sides of each GaN layer (Fig.…”

“…A R SH of 37 Ω/sq was demonstrated in a 7-channel AlN/GaN heterostructure, 63 and the 4-inch, 5-channel AlGaN/GaN wafer is commercially available with a R SH of 115 Ω/sq. 64 On the other hand, the doped multi-channel usually has impurity 43,67 or modulation doping 66 selectively introduced in each barrier layer to boost 2DEG densities, leaving the quantum well in GaN undoped to minimize the ion scattering and preserve 𝜇 . A R SH of 67 Ω/sq was reported in a modulationdoped 8-channel heterostructure 66 .…”

Design of multi-channel heterostructures for GaN devices

“…GaN devices are one of the most promising candidates for power [1][2][3] and RF [4][5][6] applications, thanks to the excellent material advantages 7) of GaN and the two-dimensional electron gas (2DEG) within its heterostructures. While GaN devices are still far from the limit, their performance can be greatly enhanced with reduced on-resistance (R on ) by increasing the density (N s ) and the mobility (μ) of the 2DEG.…”