The temperature dependence of the current–voltage characteristics Ni–GaN Schottky barriers have been measured and analyzed. It was found that enhanced tunneling component in transport current metal-GaN barrier contacts is a likely explanation for large scatter Richardson constant.

The dependence of the Schottky barrier height Ni/AlxGa1−xN contact on Al mole fraction up to x=0.23 was studied. heights were measured by I–V, capacitance–voltage, and internal photoemission method. fractions estimated from AlGaN band gap energies photoluminescence. In range x<0.2 a linear relationship between obtained. This consistent with slope predicted rule. For x=0.23, lower than predicted. We believed this due crystalline defects at Ni/AlGaN interface.

A method for enhancing effective Schottky barrier heights in III–V nitride heterostructures based on the piezoelectric effect is proposed, demonstrated, and analyzed. Two-layer GaN/AlxGa1−xN barriers within heterostructure field-effect transistor epitaxial layer structures are shown to possess significantly larger than those AlxGa1−xN, influence of composition, doping, thicknesses assessed. GaN/Al0.25Ga0.75N structure optimized heterojunction transistors yield a height enhancement 0.37 V...

Deep-level transient spectroscopy has been used to characterize electronic defects in n-type GaN grown by reactive molecular-beam epitaxy. Five deep-level were observed, with activation energies E1=0.234±0.006, E2=0.578±0.006, E3=0.657±0.031, E4=0.961±0.026, and E5=0.240±0.012 eV. Among these, the levels labeled E1, E2, E3 are interpreted as corresponding deep previously reported n-GaN both hydride vapor-phase epitaxy metal organic chemical vapor deposition. Levels E4 E5 do not correspond...

The electrical characteristics of Ni and Ti Schottky barriers on n-Al0.15Ga0.85N SiC were investigated. We report that the barrier height for was about 1.26 eV 1 or less Ti. These heights are 0.3–0.4 larger than those n-GaN, which in good agreement with model predictions.

The formation mechanism of the ohmic Au/Ni/p-GaN contact has been investigated. We found that it is essential to (i) deposit a structure Au and Ni in proper deposition sequence, (ii) anneal bilayer an oxygen containing ambient. Our findings indicated assists layer-reversal reactions metallized layers form NiO/Au/p-GaN. presence during annealing appears increase conductivity p-GaN. It further suggested removes or reduces surface contamination GaN sample before layer reversal. In final...

Platinum silicide (PtSi) and Pt Schottky contacts on n-GaN have been investigated compared. The PtSi were formed by annealing a multilayer structure of Pt/Si with the appropriate thickness ratio at 400 °C for 1 h in forming gas. barrier height as-formed was found to be 0.87 eV capacitance–voltage (C–V), remained unchanged after further 500 °C. Upon 600 h, decreased 0.74 but diodes well-behaved. as-deposited yielded 1.0 (C–V). degraded most did not survive additional longer times. electrical...

The temperature dependence of the contact resistance Ge/Pd and Si/Pd metalization scheme on n-GaAs was investigated. These two systems are based solid-phase reactions, thus leading to nonspiking ohmic contacts n-GaAs. experimental results show that behavior is likely due both a highly doped surface n+ region and/or small barrier at interface. origin this nonlinear current-voltage characteristics for certain samples also discussed.

The contact formation of Ti/Al and Ti metallization on AlGaN/GaN heterojunction field effect transistors (HFET) was investigated. It found that ohmic is related to the low work function contacting layer a TiN phase at Ti/nitride interface. Contact resistance as 1 Ω mm or less can be obtained HFET samples with nsμ product ∼0.8×1016/V s n-GaN carrier concentration 1.5×1018/cm3. bilayer scheme superior Ti-only due surface Al3Ti in contact, which may reduce oxidation problem when annealed N2...

The transport properties of the advancing interface ohmic contact to AlGaN/GaN heterostructure field-effect transistors have been investigated. We found that carrier across AlGaN barrier layer is dominated by tunneling electrons originate from two-dimensional electron gas located at interface. observed temperature dependence specific resistivity different on highly doped bulk semiconductors, although current dominates in both cases.

The electrical characteristics of Ni and NiSi Schottky diodes on n-GaN have been investigated as a function annealing. were found to be stable up 500 °C for 1 h in sequential annealing, with barrier height φ (I–V) 0.8–0.9 eV an n factor ∼1.1. deduced from C–V measurements, (C–V), was typically 0.15 higher than (I–V). At 600 the failed, Ga migrate into layer. h, about 0.8–1 n-factor 1.15. value (C–V) between 0.3 0.6 (I–V), consistent notion presence thin insulating layer at NiSi/GaN...

The internal photoemission method was used to measure the Schottky barrier height of Ni on AlGaN/GaN heterostructures. A 1.31 eV found for Ni/Al0.15Ga0.85N/GaN heterojunction structure, as compared a 1.28 and 1.02 Ni/Al0.15Ga0.85N Ni/GaN diodes, respectively.

The possible origins of the leaky characteristics a Schottky barrier on p-GaN have been investigated. as-grown samples did not show any electrical activity using Hall measurements. Ni diodes made as-activated samples, either at 950/spl deg/C for 5 s or 750/spl min exhibited quasiohmic behavior. Upon sequential etching sample to remove surface layer 150 /spl Aring/, 1200 and 5000 Aring/ from sample, I-V behavior became rectifying. I-V-T measurements showed that slopes lnI-V curves were...

The Schottky barrier characteristics of Ni on p-GaN have been investigated using current–voltage–temperature (I–V–T) and capacitance–voltage (C–V) measurements. Barrier height values ranging from 2.68 to 2.87 eV were obtained C–V temperature dependence I–V clearly indicated the dominance tunneling current in transport mechanism diodes, therefore, determination measurements can lead erroneous results, as by wide range heights reported literature. Acceptor concentration, deduced measurements,...

Al/Ti based metallization is commonly used for ohmic contacts to n-GaN and related compounds. We have previously reported an contact scheme specially designed AlGaN/GaN heterostructure field-effect transistors (HFETs) [D. Qiao et al., Appl. Phys. Lett. 74, 2652 (1999)]. This scheme, referred as the “advancing interface” contact, takes advantage of interfacial reactions between metal layers AlGaN barrier layer in HFET structure. These consume a portion barrier, thus facilitating carrier...

The process of ion cutting was used to integrate single crystalline Si layers on glass for potential active matrix flat panel display and other applications. It found that p-Si wafers implanted at 100–150 °C with H a dose in the order few times 1016 cm−2 could be readily bonded substrates when both surfaces were properly treated activated. as-implanted wafer surface converted from p type n type. Upon bonding room temperature, annealing (300 °C) exfoliation (450 °C), transferred layer...

We have investigated the use of thin film technology to introduce controllable and thermally stable stress into semiconductor heterostructures. Two simple schemes are used. The first scheme is interfacial reactions between a metal substrate, such as Ni, Co, Pd, Pt on GaAs/AlGaAs. induced in structure reproducible because volumetric change for given reaction fixed, long deposited fully reacted form compound. stability depends In case Ni Co GaAs/AlGaAs, up 600 °C. Evaporated films usually...

The critical role of the optical source spectral linewidth in semiconductor low loss waveguide measurements using Fabry–Perot resonance method is analyzed. For 5-mm-long GaAs/AlGaAs waveguides with losses 1 dB/cm range, a frequency stabilized single mode laser less than 0.01 Å required to obtain value accurate within 5%.

Specific contact resistivity ρc of planar Ge/Pd ohmic contacts to n-type AlxGa1−xAs is measured as a function AlAs mole fraction x and anneal temperature Tann. The functional dependence on Tann the same for all x, decreasing minimum at 275–325 °C. This indicates that formation mechanism independent x(0≤x≤0.3) verified by MeV Rutherford backscattering spectrometry Read camera glancing angle x-ray diffraction. Decomposition an epitaxial Pd-AlxGa1−xAs phase correlated with onset behavior may...

Purpose This study aimed to investigate dynamic change of permeability blood‐labyrinth barrier (BLB) after noise exposure and its effect on the drug delivery efficiency systemic administration. Methods Gadopentetate dimeglumine (Gd‐DTPA) dexamethasone (DEX) were used as tracers, magnetic resonance imaging (MRI) immunofluorescence observe BLB strong in guinea pigs. High‐performance liquid chromatography‐mass spectrometry (LC–MS) was breakdown intravenous DEX. The pigs divided into 6 groups:...