Gallium nitride (GaN) is one of the front-runner materials among so-called wide bandgap semiconductors that can provide devices having high breakdown voltages and are capable performing efficiently even at temperatures. The bandgap, however, naturally leads to a density surface states on bare GaN-based or interface along insulator/semiconductor interfaces distributed over energy range. These electronic lead instabilities other problems when not appropriately managed. In this Tutorial, we...

We report on frequency dependent capacitance and conductance analysis of the AlGaN/GaN/Si heterostructure field-effect transistors (HFETs) Al2O3/AlGaN/GaN/Si metal-oxide-semiconductor HFETs (MOSHFETs) in order to investigate trap effects these devices. The exhibits significantly higher dispersion than that MOSHFETs. Two different types traps were found from both devices, fast with time constant τ≅(0.1–1) μs slow τ=8 ms. density states evaluated was DT≅2.5×1012 up 1013 cm−2 eV−1 for traps,...

The authors report on improved transport properties of Al2O3∕AlGaN∕GaN metal-oxide-semiconductor heterostructure field-effect transistors (MOSHFETs). It is found that the drift mobility in MOSHFET structures with 4nm thick Al2O3 gate oxide significantly higher than HFETs. zero-bias mobilities are 1950 and 1630cm2∕Vs for HFET, respectively. An ∼40% increase saturation drain current MOSHFETs compared to HFETs seems be larger expected from passivation effects. devices show a transconductance...

We report on the frequency dependent conductance measurements of AlGaN/GaN metal-oxide-semiconductor heterostructure field-effect transistors (MOSHFETs). The properties devices with as-deposited and annealed 9-nm-thick Al2O3 gate oxide were investigated. trap density in range 1011 cm−2 eV−1 was evaluated for nonannealed devices. However, versus peaks significantly broader than those expected from theory, which indicates a surface potential fluctuation due to nonuniformities charge interface...

The trapping phenomena in GaN metal-oxide-semiconductor high-electron mobility transistor structures with 10 and 20-nm thick Al2O3 gate dielectric grown by metal-organic chemical vapor deposition were deeply investigated using comprehensive capacitance-voltage measurements. By controlling the interface traps population, substantial electron bulk was identified. Separation between process emission allowed us to determine distribution of trap density a wide energy range. Temperature dependence...

Oxide/semiconductor interface trap density (Dit) and net charge of Al2O3/(GaN)/AlGaN/GaN metal-oxide-semiconductor high-electron mobility transistor (MOS-HEMT) structures with without GaN cap were comparatively analyzed using comprehensive capacitance measurements simulations. Dit distribution was determined in full band gap the barrier combination three complementary techniques. A remarkably higher (∼5–8 × 1012 eV−1 cm−2) found at energies ranging from EC-0.5 to 1 eV for structure compared...

AlGaN/GaN metal?oxide?semiconductor heterostructure field-effect transistors (MOSHFETs) with 4 nm thick Al2O3 gate oxide were prepared and their performance was compared that of HFETs. The MOSHFETs yielded ~40% increase the saturation drain current HFETs, which is larger than expected due to passivation. Despite a gate-channel separation in MOSHFETs, higher extrinsic transconductance HFETs measured. drift mobility evaluated on large-gate FET structures, significantly zero-bias for 1950 cm2...

Atomic layer deposition (ALD) of Al2O3 was used to prepare metal-oxide-semiconductor (MOS) devices on two different_AlGaN/GaN heterostructures, with and without a thin GaN cap layer. Their trapping effects were evaluated by the frequency dependent conductance measurement. The trap state density decreased sharply from ∼1×1012 cm−2 eV−1 at energy 0.27 eV ∼3×1010 0.45 eV. low exactly exponential dependence time constant gate voltage show good quality oxide. in structure is about 2–3 times lower...

We propose a device concept for hybrid nanocrystal/III-nitride based nano-LED. Our approach is on the direct electro-optical pumping of nanocrystals (secondary excitation) by electrically driven InGaN/GaN nano-LEDs as primary excitation source. To this end, universal optoelectronic platform was developed large range optically active nano- and mesoscopic structures. The advantage that emission can be induced without need contacting them. proof principal demonstrated CdSe nanocrystals. with...

Frequency dependent conductance measurements at varied temperature between 25 and 260 °C were performed to analyze trapping effects in the Al2O3/AlGaN/GaN metal-oxide-semiconductor heterostructure field-effect transistors. The trap states with a time constant τT,f≅(0.1–1) μs (fast) τT,s=10 ms (slow) identified. increased temperatures made it possible evaluate fast about four times broader energy range than that from room measurement. density of traps decreased 1.4×1012 cm−2 eV−1 an 0.27 eV...

Hot-electron temperature (Te) in InAlN/GaN high-electron-mobility transistors (HEMTs) was determined using electroluminescence spectroscopy as a function of gate voltage and correlated with the Te distribution by hydrodynamic simulations. Good agreement between measurement simulations suggests that hot electrons can locally reach temperatures up to 30000 K at V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ds</sub> = 30 V, i.e., two three...

We report on a temperature dependent threshold voltage analysis of the AlGaN∕GaN heterostructure field-effect transistors (HFETs) and Al2O3∕AlGaN∕GaN metal-oxide-semiconductor HFETs (MOSHFETs) in order to investigate trap effects these devices. The both types devices decreases with increased ambient up 450°C. This indicates donor traps be present. induced shift is −1.6 −8.5mV∕°C for MOSHFETs, respectively. A thermally activated energy level ∼0.2eV evaluated attributed nitrogen vacancy AlGaN...

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> The RF performance of lattice-matched InAlN/GaN heterostructure field-effect transistors (HFETs) and <formula formulatype="inline"><tex Notation="TeX">$\hbox{Al}_{2}\hbox{O}_{3}$</tex></formula>/InAlN/GaN metal–oxide–semiconductor HFETs (MOSHFETs) with varied gate length was evaluated. current gain cutoff frequency Notation="TeX">$f_{T}$</tex></formula> the maximum oscillation...

A Schottky-barrier normally off InAlN-based high-electron-mobility transistor (HEMT) with selectively etched access regions, high off-state breakdown, and low gate leakage is presented. Metal-organic chemical vapor deposition-grown 1-nm InAlN/1-nm AlN barrier stack capped a 2-nm-thick undoped GaN creating negative polarization charge at GaN/InAlN heterojunction. Consequently, the effective height increased, as well equilibrium carrier concentration in channel decreased. After removal of cap...

The authors report on preparation and electrical characterization of InAlN/AlN/GaN metal-oxide-semiconductor (MOS) high electron mobility transistors (HEMTs) with Al2O3, ZrO2, GdScO3 gate dielectrics. About 10 nm thick high-κ dielectrics were deposited by metal organic chemical vapor deposition after the Ohmic contact processing. Application for 2 μm length MOS HEMTs leads to leakage current reduction from four six orders magnitude compared Schottky barrier HEMTs. Among others, an Al2O3...

We discuss possibilities of adjustment a threshold voltage VT in normally off GaN high-electron mobility transistors (HEMTs) without compromising maximal drain current IDSmax. Techniques low power plasma or thermal oxidation 2-nm thick AlN cap over 3-nm AlGaN barrier are developed and calibrated for thorough the with minimal density surface donors at inherent oxide-semiconductor interface. It has been shown that while technique leads to channel and/or interface degradation, scalability...

A local so-called laser-micro-annealing (LMA) conditioning technology, which is suitable for the fabrication of a large range hybrid nano-optoelectronic devices, was applied to III-nitride-based nano-light emitting diodes (LEDs). The LEDs with diameter ∼100 nm were fabricated in area arrays and designed optoelectronic applications. LMA process developed precise LED nano-structures. Photoluminescence measurements reveal enhancement nano-LED properties, very good agreement simple model...

The RF performance of gate recessed MISHFET devices with an amorphous AlN layer was investigated by small-signal (S-parameter) measurements. They reveal current gain and unilateral power cutoff frequencies 125 138 GHz, respectively. These device parameters were achieved for after applying a selective “step step” etching T-gate formation procedure. results indicate that the combination dielectric AlGaN/GaN structures affects in prepared high frequency operation advantageously.

Abstract The spectrometric properties of a semiconductor detector depend on both, the base material quality and electric collection field distribution. In case single pad semi-insulating (SI) bulk GaAs detectors with circular electrode collecting charge generated by radiation is affected area, thickness applied bias. Thinner smaller under higher bias obtain better such as efficiency (CCE) energy resolution (FWHM) due to more intense fewer volume defects. However, SI substrate fabrication...

The oxide/semiconductor interface state density (Dit) in Al2O3/AlGaN/GaN metal-oxide-semiconductor high-electron mobility transistor (MOS-HEMT) structures with gate oxides grown by atomic layer deposition at low temperature is analyzed this work. MOS-HEMT Al2O3 oxide were deposited 100 and 300 °C using trimethylaluminum precursor H2O O3 oxidation agents. found to show negative net charge oxide/barrier (Nint) of 1013 cm−2, which was attributed the reduction barrier surface donor (NDS). Dit...

Self‐aligned normally‐off n ++ GaN/InAlN/AlN/GaN MOS HEMTs with a recessed gate show scalable threshold voltage between 1.3 to 3.7 V, which increases the oxide thickness. Al 2 O 3 or HfO insulators were grown by ALD at 100 °C so that one photoresist mask could be used for recessing, and metal lift‐off. A low density of barrier surface donors ∼1 × 10 13 cm −2 stems from thermal budged during HEMT processing explains behaviour. Maximal I DS reaches ∼0.4 A/mm despite 2‐μm length 8‐μm...

The electrical properties of AlGaN/GaN MOSHFETs with HfO2 prepared by atomic layer deposition and w/o oxygen-plasma treatment (further referred to as PHf-MOS Hf-MOS) were investigated. sub-threshold slope the (350 150 mV dec−1 for Hf-MOS PHf-MOS, respectively) lower than that HFET (450 dec−1), which also correspond leakage current (∼10−8 A mm−1 at −9 V PHf-MOS). In addition, density interface states oxide/GaN-cap near conduction band edge mid-gap (∼5 × 1012 2 1011 cm−2 eV−1, after was (∼3...