Hydrogen incorporation depths of >25 μm were obtained in bulk, single-crystal ZnO during exposure to H2 plasmas for 0.5 h at 300 °C, producing an estimated diffusivity ∼8×10−10 cm2/V⋅s this temperature. The activation energy diffusion was 0.17±0.12 eV, indicating interstitial mechanism. Subsequent annealing 500–600 °C sufficient evolve all the hydrogen out ZnO, least sensitivity secondary ion mass spectrometry (<5×1015 cm−3). thermal stability retention is slightly greater when...

Unpassivated AlGaN/GaN high-electron-mobility transistors show significant gate lag effects due to the presence of surface states in region between and drain contact. Low-temperature (100 °C) layers MgO or Sc2O3 deposited by plasma-assisted molecular-beam epitaxy are shown effectively mitigate collapse current through passivation traps. These dielectrics may have advantages over more conventional SiNX terms long-term device stability.

We demonstrated that Sc2O3 thin films deposited by plasma-assisted molecular-beam epitaxy can be used simultaneously as a gate oxide and surface passivation layer on AlGaN/GaN high electron mobility transistors (HEMTs). The maximum drain source current, IDS, reaches value of over 0.8 A/mm is ∼40% higher Sc2O3/AlGaN/GaN relative to conventional HEMTs fabricated the same wafer. metal–oxide–semiconductor (MOS–HEMTs) threshold voltage in good agreement with theoretical value, indicating retains...

AlGaN/GaN high electron mobility transistors (HEMTs) with a range of gate lengths (0.8–1.2 μm) and widths (100–200 were exposed to 40 MeV protons at fluences 5×109 or 5×1010 cm−2. The drain–source currents in the devices decreased by 15%–20% higher fluence, while extrinsic transconductance ∼30% under same conditions. Based on increases reverse breakdown voltage channel resistance, main degradation mechanism is believed be creation deep trap states band gap which remove electrons from...

Gd 2 O 3 has been deposited epitaxially on GaN using elemental and an electron cyclotron resonance oxygen plasma in a gas-source molecular beam epitaxy system. Cross-sectional transmission microscopy shows high concentration of dislocations which arise from the large lattice mismatch between two materials. metal-oxide-semiconductor field-effect transistors (MOSFETs) fabricated dielectric stack single crystal Gd2O3 amorphous SiO2 show modulation at gate voltages up to 7 V are operational...

Gate-controlled n+p metal–oxide–semiconductor diodes were fabricated in p-GaN using MgO as a gate dielectric and Si+ implantation to create the n+ regions. This structure overcomes low minority carrier generation rate GaN allowed observation of clear inversion behavior dark at room temperature. By contrast, without regions act an external source carriers did not show even measurement temperatures 300 °C. The gated showed expected shape current–voltage characteristics, with corresponding...

Scandium oxide was deposited epitaxially on (0001) GaN via gas-source molecular beam epitaxy (GSMBE) using elemental Sc and an electron cyclotron resonance (ECR) oxygen plasma. HXRD indicated that the Sc2O3 has a lower defect density than similarly prepared films of Gd2O3. The scandium atomically smooth, with rms roughness 0.5–0.8 nm, uniform in stoichiometry as measured by Auger spectroscopy (AES) depth profiling. An interface state mid 1011 eV—1 cm—2 determined from capacitance–voltage...

This article proposes and demonstrates an optical fiber vector magnetic field sensor based on magnetofluid-encapsulated polarization-maintaining (PMF) single-end offset fusion spliced hollow-core (HCF) structure. Thanks to the unique fast slow axes structure of PMF, when two are fused with HCF, respectively, exhibits different responses variation surrounding sensing Experimental results reveal that at a dislocation <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML"...

AlGaN/GaN high electron mobility transistors (HEMTs) with different gate length and widths were irradiated Co60 γ-rays to doses up 600 Mrad. Little measurable change in dc performance of the devices was observed for lower than 300 At maximum dose employed, forward current significantly decreased, an accompanying increase reverse breakdown voltage. This is consistent a decrease effective carrier density channel as result introduction deep trapping states. The threshold voltage shifted more...

The capacitance–voltage (C–V) characteristics of Sc2O3/p-GaN gate-controlled diodes show unusual hook shapes due to the charging surface states. From drain–voltage dependence C–V curves, total state density was estimated be ∼8.2×1012 cm−2 for undergoing an implant activation anneal at 950 °C. accumulation capacitance showed a significant on measurement frequency and is suggested result from presence interfacial dielectric between Sc2O3 GaN. Si-implanted n+ regions in gated diode structure...

Edge-terminated Schottky rectifiers fabricated on quasibulk GaN substrates showed a strong dependence of reverse breakdown voltage VB contact dimension and rectifier geometry (lateral versus vertical). For small diameter (75 μm) contacts, measured in the vertical was ∼700 V, with an on-state resistance (RON) 3 mΩ cm2, producing figure-of-merit VB2/RON 162.8 MW cm−2. Measured lateral geometry, these same had ∼250 RON 1.7 cm2 36.5 The forward turn-on (VF) ∼1.8 V (defined at current density 100...

A broadband Ka-band AlGaN/GaN on SiC high electron-mobility transistor monolithic-microwave integrated-circuit (MMIC) power amplifier was developed for millimeter-wave antenna applications. The 0.18-mum gate two-stage 50-Omega matched MMIC produces 13plusmn1 dB of gain from 26 to 36 GHz. At 35 GHz, the measured continuous wave (CW) saturated output (P <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">out</sub> ) 4 W (5 pulsed), indicating a CW...

GaN metal oxide semiconductor diodes were demonstrated utilizing MgO as the gate oxide. was grown at 100°C on chemical vapor deposition n-GaN in a molecular beam epitaxy system using Mg elemental source and an electron cyclotron resonance oxygen plasma. -based wet-chemical etchant used to remove expose underlying for ohmic deposition. Electron deposited Ti/Al/Pt/Au Pt/Au utilized metallization, respectively. An interface trap density of low-to-mid- eV−1 cm−2 obtained from temperature...

The effects of hydrogen plasma treatment on high-quality bulk n-ZnO crystals were studied. It is shown that after exposure at 200 °C for 0.5 h the penetrates into material down to about 20 μm and shows concentrations close 1017 cm−3 in region. incorporation this coincides with an increase shallow donor concentration same level as hydrogen. In contrast most other semiconductor materials, ZnO already existing electron hole traps introduce near 0.55 eV, earlier observed proton irradiated...

An all-optical fiber magnetic field and temperature simultaneous measurement sensor based on single mode (SMF)-multimode (MMF)-SMF-hollow core (HCF)-SMF structure is proposed. The sensing sealed with a capillary tube infiltrated fluid (MF). By varying the external temperature, transmission spectrum of will change accordingly. spectra for variation are investigated. In experiment, sensitivity −0.865 dB/mT in range 47–60 mT 0.519 dB/°C 27 °C–43 °C obtained, respectively. Our multimode...

The low temperature (100/spl deg/C) deposition of Sc <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> or MgO layers is found to significantly increase the output power AlGaN/GaN HEMTs. At 4 GHz, there was a better than 3 dB in 0.5×100 μm <sup xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> HEMTs for both types oxide passivation layers. Both and produced larger increases at GHz...

Multi-quantum-well GaN/InGaN heterojunction diodes prepared by metalorganic chemical vapor deposition on sapphire showed effects of strong tunneling in their I–V characteristics. The space charge region was shown to be located the superlattice (SL). injection moderately high forward currents through structure for several hours enhanced overall and facilitated faster between layers SL. These results may have relevance aging characteristics light-emitting under bias.

Three different passivation layers MgO, and were examined for their effectiveness in mitigating surface-state-induced current collapse AlGaN/GaN high electron mobility transistors (HEMTs). The plasma-enhanced chemical vapor deposited produced ∼70-75% recovery of the drain-source current, independent whether or plasma chemistries employed. Both MgO essentially complete GaN-cap HEMT structures ∼80-90% AlGaN-cap structures. had superior long-term stability, with no change behavior over 5 months...

A comparison was made of specific contact resistivity and morphology Ti/Al/Pt/WSi/Ti/Au Ti/Al/Pt/W/Ti/Au ohmic contacts to AlGaN/GaN heterostructures relative the standard Ti/Al/Pt/Au metallization. The W- WSi-based show comparable resistivities that on similar layer structures, reaching minimum values ∼10−5 Ω cm2 after annealing in range 850–900 °C. However, exhibit much smoother surface morphologies, even 950 °C annealing. For example, root-mean-square roughness annealed at unchanged from...

Sc 2 O 3 -passivated AlGaN/GaN high electron mobility transistors (HEMTs) were irradiated with 40 MeV protons to a fluence corresponding approximately 10 years in low-earth orbit (5×109 cm−2). Devices an AlGaN cap layer showed less degradation dc characteristics than comparable GaN-cap devices, consistent differences average band energy. The changes device performance could be attributed completely bulk trapping effects, demonstrating that the effectiveness of Sc2O3 layers passivating...

GaN-based metal oxide semiconductor field effect transistors (MOSFETs) were demonstrated using a stacked gate consisting of single-crystal and amorphous provides good oxide/semiconductor interface reduces the leakage current enhances breakdown voltage. Charge modulation n-channel depletion mode MOSFET was achieved for voltage from +2 to −4 V. The source-drain exceeded 80 An intrinsic transconductance 61 mS/mm obtained at gate-source drain-source bias −0.5 20 V, respectively. This is first...