Power electronics is having a moment. From electric vehicles to data centers, grid infrastructure to fast chargers, the world’s appetite for converting and controlling electrical energy has never been greater, and the transistors that do this work sit at the heart of a quiet but relentless performance race. A commentary by Andrew T. Binder and Robert J. Kaplar of Sandia National Laboratories, published in Nature Electronics, examines a development that could reshape that race: the demonstration of gallium nitride high-electron-mobility transistors built with a superjunction structure that distributes electric fields in a way previously thought to be the exclusive territory of silicon technology. The work, highlighted in a News & Views piece published on 14 September 2026, suggests that polarization effects, long seen as both the blessing and the curse of gallium nitride devices, can be harnessed to push the average breakdown field of these transistors toward its theoretical limit.
To understand why this matters, it helps to revisit a fundamental trade-off in power semiconductor devices. Every transistor intended to switch high voltages must withstand a large electric field across its drift region when turned off. The thickness and doping of that drift region determine both how much voltage the device can block and how much resistance it presents to current when turned on. For decades, engineers have fought against a hard constraint known as the material’s limit: the product of the breakdown voltage and the on-resistance, scaled by the die area, cannot fall below a value set by the critical electric field and the mobility of the semiconductor. Silicon carbide and gallium nitride, with critical fields roughly ten times that of silicon, offer an order-of-magnitude advantage, but realizing that advantage in practice requires far more cleverness than simply shrinking a silicon design.
The superjunction is one of the most elegant tricks ever devised to beat this constraint. Introduced commercially in silicon power devices in the late 1990s, the superjunction replaces the conventional lightly doped drift layer with an array of alternating columns of p-type and n-type material, precisely charge-balanced so that they compensate one another. When the device blocks voltage, the compensated structure acts like an almost intrinsic layer, but with a twist: the lateral electric fields created between the columns flatten the vertical field profile, so that instead of spiking near one junction and decaying rapidly, the field becomes nearly uniform throughout the drift region. Because avalanche breakdown is triggered wherever the local field first exceeds the critical value, evening out the field allows the average field, and therefore the breakdown voltage for a given drift thickness, to climb dramatically. In silicon, this permitted a breakthrough in the trade-off between blocking voltage and conduction loss, with the on-resistance becoming nearly independent of doping and instead scaling with the pitch of the charge-balanced columns.
Transplanting the concept to gallium nitride has proven stubbornly difficult, and the reasons are rooted in the very material properties that make gallium nitride attractive in the first place. The workhorse of gallium nitride power electronics is the high-electron-mobility transistor, which relies on the strong spontaneous and piezoelectric polarization of the wurtzite crystal structure to generate a two-dimensional electron gas at the interface with an aluminum gallium nitride barrier. This polarization-induced sheet charge can reach densities far beyond what ordinary doping achieves, enabling extraordinarily low on-resistance. But the same polarization charge is fixed to the crystal lattice and to the alloy composition; it cannot be modulated by applied gate voltages, and it cannot easily be compensated by acceptors in the way silicon superjunction designers compensate their dopant columns. Creating p-type columns in gallium nitride is also far harder than in silicon, because magnesium acceptor activation requires demanding processing, and achieving the precise charge balance between polarization charge and compensation charge over micron-scale columns pushes fabrication to its limits.
Previous attempts to bring field-distribution concepts into gallium nitride have taken several forms. Researchers have used field plates, edge terminations, and graded barrier layers to smooth out electric field peaks, and proposed vertical device architectures that exploit the bulk of thick gallium nitride layers. Theoretical proposals for polarization superjunctions, in which alternating polarization dipoles perform the same charge-balancing role as doped columns in silicon, have circulated in the literature for years, but experimental realization lagged behind. Earlier experimental work on related structures, and analyses of how polarization can substitute for acceptor doping in field management, established pieces of the puzzle. What the newly highlighted research by Mazzone and colleagues delivers, according to the commentary, is a gallium nitride transistor in which a superjunction capable of effectively distributing electric fields pushes the average breakdown field toward the theoretical limit of the material.
The technical significance of that achievement is best appreciated through numbers. The theoretical limit for the average breakdown field in gallium nitride is a substantial fraction of its critical electric field, roughly 3.3 megavolts per centimeter for the bulk material. In conventional lateral gallium nitride high-electron-mobility transistors, fields tend to crowd under the gate edge and at the drain-side edge of the gate, so the average field across the drift region at breakdown is typically far lower than the peak the material can sustain. A structure that levels the field profile can therefore raise breakdown voltage at fixed drift length, or equivalently shorten the drift region for a given voltage rating, cutting on-resistance and shrinking the die. Because the Baliga figure of merit, which quantifies this trade-off, scales with the cube of the critical field, every incremental improvement in how uniformly the field is distributed translates into outsized gains in achievable performance.
The commentary by Binder and Kaplar places the new demonstration in the context of this long arc of development, drawing on a body of work that spans the founding literature of the superjunction concept in silicon, analyses of how polarization dipoles could perform the charge-balancing function in gallium nitride, and experimental studies of polarization-engineered field management in gallium nitride devices. Their perspective emphasizes that the new result is not merely an incremental device demo but a validation of a design principle: that the polarization charge, which device designers once had to work around, can be enlisted as an active engineering resource for field shaping. In effect, the fixed polarization dipoles of the wurtzite lattice take on the role that ionized dopants play in a silicon superjunction, providing built-in lateral fields that keep the vertical field flat across the blocking structure.
There are, of course, formidable engineering challenges between such a demonstration and commercial deployment. Charge balance in a superjunction is exquisitely sensitive to dimensional tolerances; in silicon, deviations of even a few percent in column width or doping concentration degrade the blocking characteristics noticeably, and the effective lateral doping problem in gallium nitride is if anything stricter because the compensating charge is set by alloy composition and strain rather than by an adjustable implantation dose. The epitaxial growth processes needed to form the alternating structures must maintain precise control over composition, thickness, and strain, since strain relaxation would alter the piezoelectric polarization on which the whole scheme depends. Thermal management, dynamic on-resistance, reliability under repetitive high-field stress, and the integration of such structures with existing gate driver and package ecosystems all remain open questions that the commentary implicitly flags as the next frontier.
Nevertheless, the implications are broad. If polarization-enabled superjunction architectures can be manufactured at scale, they could allow gallium nitride devices to extend from the several-hundred-volt range, where they are already displacing silicon in consumer chargers and data center power supplies, into the multi-kilovolt territory currently dominated by silicon carbide in electric vehicle drivetrains, industrial motor drives, and grid applications. The commentary notes that by effectively distributing electric fields, such transistors push the average breakdown field toward the theoretical limit, which is precisely the condition under which the intrinsic material advantage of gallium nitride is most fully converted into system-level benefits: smaller magnetics, higher switching frequencies, lower conversion losses, and denser power electronics. For a field in which every percentage point of efficiency translates into megawatts of saved energy at scale, flattening an electric field profile may prove to be one of the most consequential acts of engineering elegance in modern power electronics.
Subject of Research: Polarization-enabled superjunction structures in gallium nitride high-electron-mobility power transistors
Article Title: Polarization takes on the superjunction challenge
Article References: Binder, A. T., & Kaplar, R. J. (2026). Polarization takes on the superjunction challenge. Nature Electronics. https://doi.org/10.1038/s41928-026-01687-0
Image Credits: AI Generated
DOI: 10.1038/s41928-026-01687-0
Keywords: gallium nitride, superjunction, high-electron-mobility transistor, power electronics, electric field distribution, breakdown voltage, polarization charge, on-resistance, Baliga figure of merit, semiconductor devices, field plates, silicon carbide
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Denise Maddox. (September 14, 2026). Polarization Superjunctions Push Gallium Nitride Power Transistors Toward Their Theoretical Limits. Scienmag. https://scienmag.com/polarization-superjunctions-push-gallium-nitride-power-transistors-toward-their-theoretical-limits/
Denise Maddox. “Polarization Superjunctions Push Gallium Nitride Power Transistors Toward Their Theoretical Limits.” Scienmag, 14 September 2026, https://scienmag.com/polarization-superjunctions-push-gallium-nitride-power-transistors-toward-their-theoretical-limits/. Accessed 14 September 2026.
Denise Maddox. “Polarization Superjunctions Push Gallium Nitride Power Transistors Toward Their Theoretical Limits.” Scienmag. September 14, 2026. https://scienmag.com/polarization-superjunctions-push-gallium-nitride-power-transistors-toward-their-theoretical-limits/
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Tags: Baliga figure of meritbreakdown voltageelectric field distributionelectric field management in semiconductorselectric vehicle power conversionfield platesgallium nitrideGallium Nitride power transistorsGaN device breakdown fieldhigh electron mobility transistorshigh-electron-mobility transistorhigh-voltage GaN transistorslimits of GaN transistor performanceon-resistanceoptimization of GaN for power applicationspolarization chargepolarization effects in GaNpower electronicspower electronics advancementssemiconductor devicessilicon carbidesuperjunctionsuperjunction design in GaNsuperjunction structures
