A high activation ratio of acceptors to Mg ions implanted into a homoepitaxial GaN layer was achieved through an ultra-high-pressure annealing (UHPA) process. Capless under nitrogen pressure 1 GPa in temperature range 1573–1753 K activated without thermally decomposing the layer. Conventional rapid thermal leads serious decomposition at 1573 K, even with AlN protective cap. The sample annealed 1673 UHPA exhibited very intense cathodoluminescence near-band edge and donor-acceptor-pair band...

We report on homoepitaxial GaN p-n junction diodes with a negative beveled-mesa termination. The electric field distribution in was investigated using TCAD simulation, and the devices were designed currently available growth techniques. Shallow-angle (ca. 10°) bevel fabricated various Mg acceptor concentrations p-layers. suppression of crowding improvement breakdown voltage observed, as concentration decreased. parallel-plane 2.86 MV/cm obtained for device 425 V.

Abstract Magnesium ion implantation has been performed on a GaN substrate, whose surface high thermal stability, thus allowing postimplantation annealing without the use of protective layer. The current–voltage characteristics p–n diodes fabricated showed distinct rectification at turn-on voltage about 3 V, although leakage current varied widely among diodes. Coimplantation with magnesium and hydrogen ions effectively suppressed currents device-to-device variations. In addition, an...

Avalanche multiplication characteristics in a reverse-biased homoepitaxial GaN p–n junction diode are experimentally investigated at 223–373 K by novel photomultiplication measurements utilizing above- and below-bandgap illumination. The device has non-punch-through one-side abrupt p–-n+ structure, which the depletion layer mainly extends to p-type region. For above-bandgap illumination, light is absorbed surface p+-layer, generated electrons diffuse reach layer, resulting an...

The fabrication processes of p-type regions for vertical GaN power devices are investigated. A body layer in a trench gate metal-oxide-semiconductor field-effect transistor requires precise control the effective acceptor concentration, which is equal to difference between Mg concentration (Na) and compensating donor (Nd). carbon atoms incorporated during growth via metalorganic vapor phase epitaxy substitute nitrogen sites (CN) function as sources layer. Since interstitial H (Hi) also...

The role of carbon impurities in p-type GaN layers grown by metalorganic vapor phase epitaxy (MOVPE) was investigated. lightly Mg-doped (∼1017 cm−3) samples with different concentration [C] were prepared controlling growth temperature and pressure. Temperature-dependent Hall-effect analyses exhibited an increase donor increasing [C]. low-temperature mobility also decreased [C], as a result limitation due to ionized impurity scattering. These results show that atoms MOVPE-grown p-GaN act...

The source of carrier compensation in metalorganic vapor phase epitaxy (MOVPE)-grown n-type GaN was quantitatively investigated by Hall-effect measurement, deep-level transient spectroscopy, and secondary ion mass spectrometry. These analysis techniques revealed that there were at least three different sources. for samples with donor concentrations below 5 × 1016 cm−3 can be explained residual carbon electron trap E3 (EC − 0.6 eV). For higher concentrations, we found a proportional...

We investigated traps in lightly Mg-doped (2 × 1017 cm−3) p-GaN fabricated by metalorganic vapor phase epitaxy (MOVPE) on a freestanding GaN substrate and the subsequent post-growth annealing, using deep level transient spectroscopy. identified four hole with energy levels of EV + 0.46, 0.88, 1.0, 1.3 eV one electron trap at EC − 0.57 p-type layer uniformly doped magnesium (Mg). The Arrhenius plot highest concentration (∼3 1016 located 0.88 corresponded to those ascribed carbon nitrogen...

In this study, the authors systematically investigate electrical properties and reliability of Al2O3/SiO2 nanolaminate films with different compositions on GaN. Leakage current in nanolaminates was suppressed by higher SiO2 content due to enhancement conduction band offset between The interface-trap density (Dit) at nanolaminates/GaN as good those Al2O3/GaN SiO2/GaN interfaces. lifetime increased increasing content. addition, demonstrated that thickness ratio 0.21 had almost same Al2O3 under...

We demonstrated a wide range of magnesium (Mg) doping control (1016–1020 cm−3) in GaN layer grown by metalorganic vapor phase epitaxy on freestanding substrate and investigated the defect states at low high Mg concentrations ([Mg]). Hydrogen ([H]) as-grown samples showed one-to-one relationship with [Mg] over 6 × 1016–3 1019 cm−3 due to formation Mg-H complexes but exhibited gaps between [H] ends range. At [Mg], we found that was good agreement sum carbon (C) concentrations, indicating C-H...

Diffusion in a magnesium (Mg)-implanted homoepitaxial GaN layer during ultra-high-pressure annealing (UHPA, ambient nitrogen, under 1 GPa) was investigated. Annealing at 1573 K resulted Mg-segregation the edge of implanted region, which suppressed using higher temperature 1673 K. Hydrogen (H) atoms were incorporated UHPA, resulting Mg and H developing same diffusion profile deeper region. The coefficient Mg-implanted sample 3.3 × 10−12 cm2 s−1 from duration dependence, 30 times larger than...

Defects in Mg ion-implanted GaN epitaxial layers formed after annealing at 1573 K and 1753 were analyzed by transmission electron microscopy. Degradation of the surface, which occurs temperatures higher than about K, was avoided ultra-high-pressure under a N2 atmosphere 1 GPa. Annealing for damage recovery compound semiconductors generally requires two-thirds their melting point, is reportedly 2518 or GaN. Thus, defect analysis annealed necessary to understand recovery. Atomic-resolution...

AME Aquatic Microbial Ecology Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout JournalEditorsSpecials 24:203-207 (2001) - doi:10.3354/ame024203 Contribution of methanotrophs freshwater macroinvertebrates: evidence from stable isotope ratios S. I. Kiyashko1,*, T. Narita2, E. Wada2 1Institute Marine Biology FEB RAS, Vladivostok 690041, Russia 2Center for Ecological Research Kyoto University, Otsu 520-2113, Japan *E-mail:...

Photoluminescence (PL) spectra of (0001¯) N-polar p-type GaN fabricated by using the sequential ion-implantation Mg and H with subsequent high temperature annealing exhibited near-band-edge (NBE) emission at 300 K. The longest PL lifetime (τPL) for NBE sample concentrations 1 × 1019 2 1020 cm−3, respectively, annealed 1230 °C was 18 ps This value is almost comparable to that (0001) Ga-polar Mg-doped (p-GaN:Mg) homoepitaxial film same concentration. By correlating τPL concentration major...

Sources of carrier compensation in n-type and p-type GaN layers grown by metalorganic vapor phase epitaxy were quantitatively identified a combination Hall-effect analysis deep level transient spectroscopy. For GaN, we three electron sources: residual carbon atoms likely sitting on nitrogen sites (CN), an trap at the energy EC –0.6 eV (the E3 trap), self-compensation appearing with increasing donor concentration. We showed that CN also play key role hole forming donor-like charged states....

The origin of E3 electron traps at EC –0.58 eV in GaN was investigated using Si-doped n-type layers grown on freestanding substrates MOVPE. These contained impurity Fe various concentrations depending the growth conditions and position within wafer. Twenty (NT,E3) determined by deep-level transient spectroscopy were plotted against corresponding ([Fe]) obtained from secondary ion mass spectrometry. A correlation evident between NT,E3 [Fe] range (0.4–12) × 1015 cm–3, suggesting that level...

Vacancy‐type defects in Mg‐implanted GaN with and without hydrogen (H) implantation are probed by using monoenergetic positron beams. Mg + H ions implanted into GaN(000) to obtain 0.1 0.7‐µm‐deep box profiles concentrations of 1 × 10 19 2 20 cm −3 , respectively. For the as‐implanted samples, major defect species is determined be Ga‐vacancy ( V Ga ) related such as divacancy N ), their complexes impurities. an agglomeration vacancies starts at 800 °C annealing, leading formation vacancy...

The lowest resistivity of highly Si-doped Al0.62Ga0.38N was achieved using metalorganic vapor epitaxy. strongly depended on the Si concentrations and reached a minimum value 6.6 × 10−3 Ω cm at concentration 3.2 1019 cm−3, where carrier close to one. Above this concentration, luminescence bands around 2.4 eV originating from group-III-vacancy–Si complexes (VIII–nSi) were observed, whereas mobilities decreased. Growth conditions that avoid high temperatures V/III ratios result in suppressed...

The electrical stabilities of AlSiO gate oxides formed through post-deposition annealing (PDA) and intended for GaN-based power devices were assessed. No degradation the interface properties AlSiO/n-type GaN or oxide breakdown voltage was observed, even after PDA up to 1050 °C. Furthermore, higher temperature drastically reduced trap density in oxide, as indicated by current–voltage positive bias instability data. Time-to-breakdown characteristics showed sufficient lifetimes above 20 years...

AlGaN-based ultraviolet light-emitting diodes (UV-LEDs) are key components for the inactivation of viruses. Highly efficient and high-power UV-LEDs, capable inactivating viruses in a short time, demand. For this purpose, growth technologies n-type AlGaN contact layers were developed from two points view: first, to decrease resistivity Al0.62Ga0.38N by minimizing electron compensation, resulting electronic degeneracy with metallic conduction; second, improve light emission uniformity...

A nearly-ideal edge termination for GaN p–n junctions was designed and demonstrated using Mg-ions implanted field limiting rings (FLRs). The FLRs were fabricated via the ultra-high-pressure annealing process after implanting into etched n-type region outside main junction. results of technology computer-aided design simulation indicate that by optimizing space width rings, breakdown voltage (BV) can be increased over 90% ideal parallel plane BV (973 V). Accordingly, diodes exhibited low...

Abstract Power devices are operated under harsh conditions, such as high currents and voltages, so degradation of these is an important issue. Our group previously found significant increases in reverse leakage current after applying continuous forward stress to GaN p–n junctions. In the present study, we identified type threading dislocations that provide pathways for this current. diodes were grown by metalorganic vapor phase epitaxy on freestanding GaN(0001) substrates with dislocation...

Vertical GaN junction barrier Schottky (JBS) diodes with superior electrical characteristics and nondestructive breakdown were realized using selective-area p-type doping via Mg ion implantation subsequent ultra-high-pressure annealing. Mg-ion was performed into a 10 μm thick Si-doped drift layer grown on free-standing n-type substrate. We fabricated the JBS different channel widths Ln = 1 1.5 μm. The diodes, depending Ln, exhibited on-resistance (RON) between 0.57 0.67 mΩ cm2, which is...

P-type doping in selected areas of gallium nitride (GaN) using magnesium (Mg)-ion implantation and subsequent ultra-high-pressure annealing (UHPA) are investigated to improve the performance vertical GaN power devices. UHPA allows a high-temperature process without decomposition surface virtually complete activation implanted Mg ions GaN. In present paper, we provide an overview recent challenges making more realistic as industrial process. Instead at than 1400 °C for short duration,...

Abstract By controlling a metal-oxide-semiconductor interface of an AlSiO/GaN system, the electron inversion channel mobility was significantly improved to 229 cm 2 V −1 s in field-effect transistor. A 3 nm thick AlN interlayer formed by atomic layer deposition effectively suppressed oxidation GaN surface and reduced border traps, resulting high mobility. An additional nitrogen radical treatment before further subthreshold slope mobility, which consistent with lower charged defects extracted...