Power and RF electronics applications have spurred massive investment into a range of wide ultrawide bandgap semiconductor devices which can switch large currents voltages rapidly with low losses. However, the end systems using these are often limited by parasitics integrating driving chips from silicon complementary metal-oxide-semiconductor-based design (CMOS) circuitry necessary for complex control logic. For that reason, implementation CMOS logic directly in platform has become way each...

In evaluating GaN high-electron mobility transistors (HEMTs) for high-power applications, it is crucial to consider the device-level breakdown characteristics. This letter replaces conventional AlGaN barrier and common backbarrier with unstrained AlN, assesses voltage of AlN/GaN/AlN quantum well HEMTs gate-drain spacings in range 0.27-5.1 μm. The results are highlighted by a high 78 V spacing 390 nm, among best reported submicron-channel devices. addition, small-signal RF measurements showed...

Abstract Gallium nitride high-electron-mobility transistors (GaN HEMTs) are at a point of rapid growth in defense (radar, SATCOM) and commercial (5G beyond) industries. This also comes which the standard GaN heterostructures remain unoptimized for maximum performance. For this reason, we propose shift to aluminum (AlN) platform. AlN allows smarter, highly-scaled heterostructure design that will improve output power thermal management III-nitride amplifiers. Beyond improvements over incumbent...

Epitaxial AlN thin-film bulk acoustic resonators (FBARs) on SiC substrates with first-order thickness extensional modes of 15-17 GHz are demonstrated. For the 15 epi-AlN FBARs, quality factor <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${Q}_{\textit {ma}{x}}\approx {443}$ </tex-math></inline-formula> , electromechanical coupling coefficient notation="LaTeX">${k}_{\textit {ef}{f}}^{{2}}\approx {2}.{3}\%$...

The AlN/GaN/AlN heterostructure is attractive for microwave and millimeter-wave power devices due to its thin top barrier, tight carrier confinement, improved breakdown voltage. This work explores the large-signal RF performance of high-electron-mobility transistors on this heterostructure. Results are highlighted by record high on-current 3.6 A/mm, maximum oscillation frequency (f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">max</sub> ) 233...

Due to its high breakdown electric field, the ultra-wide bandgap semiconductor AlGaN has garnered much attention recently as a promising channel material for next-generation electron mobility transistors (HEMTs). A comprehensive experimental study of effects Al composition x on transport and structural properties is lacking. We report charge control polarization-induced 2D gases (2DEGs) in strained quantum well channels molecular-beam-epitaxy-grown AlN/AlxGa1−xN/AlN double heterostructures...

The long-missing polarization-induced two-dimensional hole gas is finally observed in undoped gallium nitride quantum wells. Experimental results provide unambiguous proof that a 2D GaN grown on AlN does not need acceptor doping, and can be formed entirely by the difference internal polarization fields across semiconductor heterojunction. measured densities, about $4 \times 10^{13}$ cm$^{-2}$, are among highest all known semiconductors remain unchanged down to cryogenic temperatures. Some of...

RF plasma assisted MBE growth of scandium nitride (ScN) thin films on Ga-polar GaN (0001)/SiC, Al-polar AlN (0001)/Al2O3, and Si-face 6H-SiC (0001) hexagonal substrates is found to lead a face centered cubic (rock salt) crystal structure with (111) out-of-plane orientation instead orientation. Cubic twinned patterns in ScN are observed by situ electron diffraction during epitaxy, the twin domains detected backscattered further corroborated X-ray diffraction. The epitaxial display very...

A high-conductivity two-dimensional (2D) hole gas is the enabler of wide-bandgap p-channel transistors. Compared to commonly used AlN template substrates with high dislocation densities, recently available single-crystal are promising boost speed and power handling capability transistors based on GaN/AlN 2D gases (2DHGs) thanks much lower densities absence thermal boundary resistance. Using plasma-assisted molecular beam epitaxy, we report observation polarization-induced high-density 2DHGs...

High-performance p-channel transistors are crucial to implementing efficient complementary circuits in wide-bandgap electronics, but progress on such devices has lagged far behind their powerful electron-based counterparts due the inherent challenges of manipulating holes wide-gap semiconductors. Building recent advances materials growth, this work sets simultaneous records both on-current (10 mA/mm) and on-off modulation (four orders) for GaN/AlN p-FET structure. A compact analytical pFET...

High-performance wide-bandgap p-channel devices which can be monolithically integrated with established n-channel are broadly desirable to expand the design topologies available in power/RF electronics. This work advances GaN-on-AlN platform as most promising contender enable complementary Toward that end, a new generation of HFET s is fabricated on-currents exceeding 100 mA/mm at room temperature under moderate drain bias. Key fabrication ingredients this success discussed, low-temperature...

To make complementary GaN electronics a desirable technology, it is essential to understand the low mobility of 2D hole gases in III-Nitride heterostructures. This work derives both acoustic and optical phonon spectra present one most prominent p-channel heterostructures (the all-binary GaN/AlN stack) computes interactions these with gas, capturing temperature dependence its intrinsic mobility. Finally, effects strain on electronic structure confined gas are examined means proposed engineer...

High-conductivity undoped GaN/AlN 2D hole gases (2DHGs), the p-type dual of AlGaN/GaN electron (2DEGs), have offered valuable insights into transport in GaN and enabled first GHz RF p-channel FETs. They are an important step towards high-speed high-power complementary electronics with wide-bandgap semiconductors. These technologically scientifically relevant perceived to be not as robust 2DEGs because structurally similar heterostructures exhibit wide variations density over $\Delta p_s >$ 7...

Using epitaxial aluminum nitride (AlN) developed for ultraviolet photonics and high-speed electronics, we demonstrate suspended AlN thin-film bulk acoustic resonators (FBARs) at 9.2 GHz in the X-band (8–12 GHz) of microwave spectrum. The show a Qmax≈614 figure merit f⋅Q≈5.6 THz. material stack these epi-AlN FBARs allows monolithic integration with AlN/GaN/AlN quantum well high-electron-mobility-transistors to unique RF front end also enable superconductors filters computing.

Abstract High hole densities are desired in p‐channel field effect transistors to improve the speed and on‐currents. Building on recently discovered undoped, polarization‐induced GaN/AlN 2D gas (2DHG), this work demonstrates tuning of piezoelectric polarization difference across heterointerface by introducing indium GaN channel. Using careful design epitaxial growths, these pseudomorphic (In)GaN/AlN heterostructures result some highest carrier &gt;10 14 cm −2 a III‐nitride...

We present a compositional dependence study of electrical characteristics AlxGa1−xN quantum well channel-based AlN/AlGaN/AlN high electron mobility transistors (HEMTs) with x=0.25,0.44, and 0.58. This ultra-wide bandgap heterostructure is candidate for next-generation radio frequency power electronics. The use selectively regrown n-type GaN Ohmic contacts results in contact resistance that increases as the Al content channel increases. DC HEMT device reveal maximum drain current densities...

We report on GaN-based field effect transistors with laterally-gated multiple 2DEG channels, called BRIDGE FETs (buried dual gate FETs). Unique operation principle of the demonstrated unprecedented device characteristics suitable for efficient and linear millimeter-wave power amplifier applications. Multiple channels formed in AlGaN/GaN AlN/GaN material systems are compatible BRIDE FET structure, adding design flexibility an increased drain current density higher frequency performance. The...

A strong need exists for a wide-bandgap p-type transistor counterpart of the n-channel GaN HEMTs power electronics and novel RF circuits. In this work, first p-channel nitride transistors that break GHz speed barrier are demonstrated. By leveraging unique single-channel high-density polarization-induced 2D hole gas GaN/AlN heterostructure, best-in-class contact resistances, scaled T-gate design, on-currents 428 mA/mm observed, with cutoff frequencies in 20 regime. These observations...

Large‐area growth of polarization‐induced 2D hole gases (2DHGs) in a GaN/AlN heterostructure using molecular beam epitaxy (MBE) is demonstrated. A study the effect metal fluxes and substrate temperature during conducted to optimize 2DHG transport. These conditions are adopted for on 2 in. wafer substrates. The obtained results represent step forward towards achieving platform high‐performance wide‐bandgap p‐channel field transistors (FETs).

The recent demonstration of W mm −1 output power at 94 GHz in AlN/GaN/AlN high‐electron‐mobility transistors (HEMTs) has established AlN as a promising platform for millimeter‐wave electronics. current state‐of‐art HEMTs using ex situ‐deposited silicon nitride (SiN) passivation layers suffer from soft gain compression due to trapping carriers by surface states. Reducing state dispersion these devices is thus desired access higher powers. Herein, potential solution novel situ crystalline...

Undoped GaN/AlN heterostructures with a high‐density 2D hole gas (2DHG) have recently been reported, demonstrating that holes can be generated in GaN without magnesium (Mg) doping. The presence of the 2DHG these is expected to result from huge internal polarization fields. Herein, modulation spectroscopy applied analyze built‐in electric fields top layer molecular beam epitaxy (MBE)‐grown buried using contactless electroreflectance (CER). Experimentally obtained field values are compared...

We report studies on the nanoscale transport dynamics of carriers in strained AlN/GaN/AlN quantum wells: an electron-hole bilayer charge system with a large difference properties between layers. From electronic band diagram analysis, presence spatially separated two-dimensional electron and hole layers is predicted at opposite interfaces. Since these exhibit distinct spectral signatures terahertz frequencies, combination far-infrared spectroscopy enables us to extract (a) individual...

Although the scanning microwave microscope (SMM) is based on atomic force (AFM), SMM differs from AFM by being able to sense subsurface electromagnetic properties of a sample. This makes promising for in-depth nondestructive characterization nanoelectronic structures. However, raw data are convoluted with sample topography, making it especially challenging quantitative nonplanar In this paper, using topography information simultaneously obtained and in situ extracted probe geometry, we...

Aluminum nitride (AlN) offers novel potential for electronic integration and performance benefits high‐power, millimeter‐wave amplification. Herein, load‐pull power at 30 94 GHz AlN/GaN/AlN high‐electron‐mobility transistors (HEMTs) on silicon carbide (SiC) is reported. When tuned peak power‐added efficiency (PAE), the reported HEMT shows PAE of 25% 15%, with associated output () 2.5 1.7 W mm −1 , GHz, respectively. At maximum generated 2.2 13%.

Abstract We report on highly-scaled Al 0.25 Ga 0.75 N channel high electron mobility transistors. Regrown ohmic contacts covering the sidewall of compressively strained exhibited a low contact resistance R c = 0.23 Ω · mm. Scaled devices with T-shaped gate showed record speed for any AlGaN-based transistors, f T / max 67/166 GHz, while simultaneously achieving average breakdown field exceeding 2 MV cm −1 . The load-pull measurements performed at 10 GHz revealed 20% peak power added...