Characteristics Of In0 Research Articles

Impact of AlN interlayer on the electronic and I-V characteristics of In0.17Al0.83N/GaN HEMTs devices

Here, we study a simulation model of In0.17Al0.83N/GaN passivated high electron mobility transistors (HEMTs) on SiC substrate. The research focused systematically on the effet of AlN interlayer on the electronic and electric characteristics using the Nextnano simulation software. The 2D–electron gas density of In0.17Al0.83N/AlN/GaN HEMTs is investigated through the dependence on various AlN layer thickness, we report calculations of I-V characteristics, with 1.5 nm AlN thickness, we find the highest maximum output current of 1.81 A/mm at Vgs 1 V, and more than 450 mS/mm as a transconductance peak. The Results are in agreement with experimental data.

Effect of In0.83Al0.17As Multiplication Layer on Characteristics of In0.83Ga0.17As/GaAs Avalanche Photodetector

Effect of In0.83Al0.17As Multiplication Layer on Characteristics of In0.83Ga0.17As/GaAs Avalanche Photodetector

Characteristics of In0.7Ga0.3As MOS Capacitors with Sulfur and Hydrazine Pretreatments

This paper proposes an effective pretreatment process that combines wet ammonium sulfide ((NH4)2S) dipping and hydrazine (N2H4) vapor treatment before high dielectric constant (κ, kappa) deposition to reduce native oxide and elemental arsenic (As) before atomic layer deposition of ammonium oxide (Al2O3) gate dielectrics on n-doped indium gallium arsenide (In0.7Ga0.3As) layers to form metal oxide semiconductor capacitors (MOSCAPs). X-ray photoelectron spectroscopy (XPS) analysis confirms that sulfuration of In0.7Ga0.3As surface by (NH4)2S solution dipping can effectively reduce indium–oxygen (In–O), gallium–oxygen (Ga–O), arsenic–oxygen (As–O) bonds while elemental As still exist at the high-κ/In0.7Ga0.3As interface. Furthermore, N2H4 treatment on sulfurated In0.7Ga0.3As can effectively suppress the native oxides and elemental As. Accordingly, the obtained data indicate that the combination of chemical sulfur pretreatment and N2H4 treatment is advantageous to passivate the trap states on In0.7Ga0.3As metal–oxide–semiconductor capacitors (MOSCAPs). Moreover, forming gas annealing (FGA) process could further improve the capacitance-voltage (C–V) characteristics and the interface trap density (Dit) of In0.7Ga0.3As MOSCAP could be reduced significantly, achieving a value of 1.2 × 1012 cm−2 eV−1.

Study of the spectral and power characteristics of In0.2Ga0.8N/GaN superluminescent light-emitting diodes by taking into account the piezoelectric polarization fields

Study of the spectral and power characteristics of In0.2Ga0.8N/GaN superluminescent light-emitting diodes by taking into account the piezoelectric polarization fields

Physical device modelling of emitter–base junction of In0.52Al0.48As/In0.53Ga0.47As-based SHBTs

ABSTRACTThis paper aims to evaluate the base–emitter forward characteristics of In0.52Al0.48As/In0.53Ga0.47As heterojunction bipolar transistors using numerical simulations in Silvaco while comparing results with fabricated devices. Analysis drawn from simulations reveals that in addition to doping, thickness of emitter and spacer region also plays an important role in determining the operational behaviour of device. The thickness of spacer region strongly influences the nature of heterojunction barrier formed that in turn controls the injection efficiency and dictates various recombination mechanisms. Even a few angstroms added to a spacer layer can cause considerable shift in DC characteristics. Methodology of device modelling is first validated by matching simulated results with the experimental measurements of two different structures. Spacer thickness and emitter doping is then varied in each of the structures to comprehensively study the effect of these variations onto important DC figures of merit.

Characteristics of In0.7Ga0.3As MOS Capacitors Obtained using Hydrochloric Acid Treatment, Ammonium Sulfide Passivation, Methanol Treatment, and Forming Gas Annealing

This paper proposes a chemical pre-treatment process to reduce sulfate prior to atomic layer deposition of Al2O3 gate dielectrics on n-doped In0.7Ga0.3As layers to form metal oxide semiconductor capacitors (MOSCAPs). Cleaning with methanol was done after hydrogen chloride etching and ammonium sulfide passivation. X-ray photoelectron spectroscopy performed on the sample with methanol cleaning indicated that its native oxide regrowth was effectively prevented on the sulfur-passivated In0.7Ga0.3As surface under air exposure. By analysis using atomic force microscopy of the sample cleaned using methanol, no further increase of surface roughness was observed after 5 months of air exposure. In addition, a mid-gap interface defect density (Dit) of 1.3 × 1012 cm−2 eV−1 was obtained from this sample. After forming gas annealing (FGA), the Dit was improved significantly, to a value below 1012 cm−2 eV−1. The obtained data indicate that the combination of chemical pre-treatment and FGA is advantageous to passivating the trap states on In0.7Ga0.3As MOSCAPs.

Low-Temperature epitaxial growth of InGaAs films on InP(100) and InP(411)A substrates

The structural and electrical characteristics of In0.53Ga0.47As epitaxial films, grown in the low-temperature mode on InP substrates with (100) and (411)A crystallographic orientations at flow ratios of As4 molecules and In and Ga atoms of γ = 29 and 90, have been comprehensively studied. The use of InP(411)A substrates is shown to increase the probability of forming two-dimensional defects (twins, stacking faults, dislocations, and grain boundaries), thus reducing the mobility of free electrons, and AsGa point defects, which act as donors and increase the free-electron concentration. An increase in γ from 29 to 90 leads to transformation of single-crystal InGaAs films grown on (100) and (411)A substrates into polycrystalline ones.

Simulation of the characteristics of InGaAs/InP-based photovoltaic laser-power converters

A method for mathematical simulation is used to analyze the efficiencies attainable in photovoltaic laser-power conversion at wavelengths of 1.3 and 1.55 μm in In0.53Ga0.47As/InP heterostructures with light input on the side of the n-InP substrate. The influence exerted on the efficiency by the parameters of the In0.53Ga0.47As/InP heterostructure and by the design of the photovoltaic laser-power converter is examined. The simulated characteristics of In0.53Ga0.47As/InP photovoltaic converters are compared with those of GaAs-based photovoltaic converters for a wavelength of 809 nm. It is shown that efficiencies of 40% at a wavelength of 1.3 μm and nearly 50% at 1.55 μm can be attained at a laser power of about 2–6 W, but the efficiency noticeably decreases at higher laser-light intensities. It is found that the main factor that hinders the achievement of a high efficiency in the conversion of high-intensity laser light is loss in the n-InP substrate. The optimal doping level of n-InP substrates to be used in the photovoltaic converters intended for varied laser-light intensities is estimated.

Comparative investigation of InGaP/GaAs/GaAsBi and InGaP/GaAs heterojunction bipolar transistors

In this article the characteristics of In0.49Ga0.51P/GaAs/GaAs0.975Bi0.025 and In0.49Ga0.51P/GaAs heterojunction bipolar transistor (HBTs) are demonstrated and compared by two-dimensional simulated analysis. As compared to the traditional InGaP/GaAs HBT, the studied InGaP/GaAs/GaAsBi HBT exhibits a higher collector current, a lower base-emitter (B–E) turn-on voltage, and a relatively lower collector-emitter offset voltage of only 7 mV. Because the more electrons stored in the base is further increased in the InGaP/GaAs/GaAsBi HBT, it introduces the collector current to increase and the B–E turn-on voltage to decrease for low input power applications. However, the current gain is slightly smaller than the traditional InGaP/GaAs HBT attributed to the increase of base current for the minority carriers stored in the GaAsBi base.

Analysis of Low Dimensional Nanoscaled Inversion-Mode InGaAs MOSFETs for Next-Generation Electrical and Photonic Applications

The electrical characteristics of In0.53Ga0.47As MOSFET grown with Si interface passivation layer (IPL) and highkgate oxide HfO2layer have been investigated in detail. The influences of Si IPL thickness, gate oxide HfO2thickness, the doping depth, and concentration of source and drain layer on output and transfer characteristics of the MOSFET at fixed gate or drain voltages have been individually simulated and analyzed. The determination of the above parameters is suggested based on their effect on maximum drain current, leakage current, saturated voltage, and so forth. It is found that the channel length decreases with the increase of the maximum drain current and leakage current simultaneously. Short channel effects start to appear when the channel length is less than 0.9 μm and experience sudden sharp increases which make device performance degrade and reach their operating limits when the channel length is further lessened down to 0.5 μm. The results demonstrate the usefulness of short channel simulations for designs and optimization of next-generation electrical and photonic devices.

Influence of the channel electric field distribution on the polarization Coulomb field scattering in In0.18Al0.82N/AlN/GaN heterostructure field-effect transistors

By making use of the quasi-two-dimensional (quasi-2D) model, the current–voltage (I–V) characteristics of In0.18Al0.82N/AlN/GaN heterostructure field-effect transistors (HFETs) with different gate lengths are simulated based on the measured capacitance–voltage (C–V) characteristics and I–V characteristics. By analyzing the variation of the electron mobility for the two-dimensional electron gas (2DEG) with electric field, it is found that the different polarization charge distributions generated by the different channel electric field distributions can result in different polarization Coulomb field scatterings. The difference between the electron mobilities primarily caused by the polarization Coulomb field scatterings can reach up to 1522.9 cm2/V·s for the prepared In0.18Al0.82N/AlN/GaN HFETs. In addition, when the 2DEG sheet density is modulated by the drain–source bias, the electron mobility presents a peak with the variation of the 2DEG sheet density, the gate length is smaller, and the 2DEG sheet density corresponding to the peak point is higher.

Determination of energy and spatial distribution of oxide border traps in In0.53Ga0.47As MOS capacitors from capacitance–voltage characteristics measured at various temperatures

In this work, we have systematically studied the frequency dispersion of the capacitance–voltage (C–V) characteristics of In0.53Ga0.47As metal–oxide-semiconductor (MOS) capacitors in accumulation region at various temperatures based on a distributed border traps model. An empirical method to evaluate the frequency and temperature dependent response of the border traps distributed along the depth from the interface into the oxide is established. While the frequency dependent response results from the dependence of the time constant of the border traps on their depths, the temperature dependent response is ascribed to the thermal activated capture cross-section of the border traps due to the phonon-related inelastic capturing process. Consequently, it is revealed that the frequency dispersion behaviors of the accumulation capacitance at different temperatures actually reflect the spatial distribution of the border traps. On this basis, we propose a methodology to extract the border trap distribution in energy and space with emphasis on analyzing the C–V characteristics measured from low to high temperatures in sequence.

Study on high mobility In0.6Ga0.4As channel MOSHEMT and MOSFET

High-mobility In0.6Ga0.4As channel metal oxide semiconductor high electron mobility transistor (MOSHEMT) and metal oxide semiconductor field effect transistor (MOSFET) are investigated based on simulation and experiment in this paper. It is found that InAlAs barrier layer has a great influence on the characteristics of In0.6Ga0.4As MOSHEMT. In0.6Ga0.4As MOSHEMT exhibits excellent electrical characteristics compared with In0.6Ga0.4As MOSFET. The experimental results show that the effective channel mobility of MOSHEMT is 2812 cm2/V·s-1, which is 3.2 times that of MOSFET. A 0.02 mm gate length MOSHEMT shows higher drive current, peak transconductance, Ion/Ioff ratio and gate breakdown voltage and lower sub-threshold swing than the MOSFET with the same gate length.

Effects of well thickness on the spectral properties of In0.5Ga0.5As∕GaAs∕Al0.2Ga0.8As quantum dots-in-a-well infrared photodetectors

We report on the effects of the quantum well (QW) thickness on the spectral response and other characteristics of In0.5Ga0.5As∕GaAs∕Al0.2Ga0.8As quantum dots-in-a-well infrared photodetectors grown by low-pressure metal-organic chemical vapor deposition. The main device properties are observed to have a strong dependence on the QW parameters.

Electrical Characteristics of InGaN/AlGaN and InGaN/GaN MQWNear UV-LEDs

Electrical characteristics ofIn0.05Ga0.95N/Al0.07Ga0.93N andIn0.05Ga0.95N/GaN multiple quantum well (MQW)ultraviolet light-emitting diodes (UV-LEDs) at 400 nm wavelength aremeasured. It is found that for InGaN/AlGaN MQW LEDs, both idealityfactor and parallel resistance are similar to those of InGaN/GaN MQWLEDs, while series resistance is two times larger. It is suggested thatthe Al0.07Ga0.93N barrier layer did not change crystalquality and electrical characteristic of p-n junction either, butbrought larger series resistance. As a result, InGaN/AlGaN MQW LEDssuffer more serious thermal dissipation problem although they showhigher light output efficiency.

Improved Device Performance of In0.5Ga0.5P/In0.22Ga0.78As/GaAs MOS p-HEMT using a Selective Liquid Phase Oxidation

ABSTRACTThe DC and RF characteristics of In0.5Ga0.5P/In0.22Ga0.78As/GaAs MOS p-HEMTs with different gate oxide thickness were investigated and compared with those of Schottky-gate p-HEMT without the gate oxide layer. The oxide layer was implemented by using a liquid phase oxidation technique. It was found that transconductance (gm), threshold voltage and breakdown voltage characteristics of MOS p-HEMTs depended strongly on the gate oxide thickness. The MOS p-HEMTs showed superior DC and RF performances compared with those of GaAs-based MOSFET having oxide/n-GaAs or oxide/InGaAs interface.

Fabrication of InP-based InGaAs ridge quantum wires utilizing selective molecular beam epitaxial growth on (311)A facets

InP-based InGaAs/InAlAs ridge quantum wires were successfully fabricated by our new approach using selective molecular beam epitaxy (MBE). As the starting structures, array of InGaAs ridge structures composed of smooth (311)A facets were formed by MBE on mesa-patterned InP substrates. Prior to actual fabrication of the wires, MBE growth characteristics of In0.53Ga0.47As and In0.52Al0.48As layers on the starting structure were studied in detail. The results of growth experiments were then successfully applied to the fabrication of InGaAs ridge quantum wires with high spatial uniformity. Low temperature cathodoluminescence spectrum measured in response to spot excitation of wire region showed a strong light emission whose analysis indicated that it originates from InGaAs ridge quantum wire itself. In photoluminescence measurements, the emission from the wire had strong intensity even at room temperature, indicating that the wire crystal possesses excellent bulk and interface quality, and are largely free from nonradiative recombination centers.

Defect evaluation and electrical characteristics of GaSb and In0.17Ga0.83Sb films grown by molecular beam epitaxy

MBE GaSb and In0.17Ga0.83Sb films are grown on GaSb(100) and GaAs(100) substrates and the film defects are investigated by using chemical etching and optical microscopic techniques. A new wet chemical etching method that revealed film defects in thin MBE GaSb and In0.17Ga0.83Sb films is evaluated, and it is found that a hot HCl solution under illumination is most effective in revealing the defects of the thin MBE films. Dislocations and stacking faults, which are related to the substrate material selected, substrate quality, substrate surface preparation, and the insertion of a buffer layer are clearly observed. In particular, in the growth of In0.17Ga0.83Sb, the huge lattice mismatch between the In0.17Ga0.83Sb and GaAs substrate causes severe dislocations, as well as stacking faults. Meanwhile, the AISb buffer layer is able to eliminate stacking faults and reduce dislocations in In0.17Ga0.83Sb films and thereby improve the electrical characteristics of the In0.17Ga0.83Sb film.

Interfacial properties of InAlAs/InGaAs HIGFETs and MIS capacitors

The interfacial properties and characteristics of In0.52Al0.48As/In0.53Ga0.47As MIS capacitors grown on InP substrates by molecular beam epitaxy and of prototype enhancement-mode heterojunction insulated gate field-effect transistors (HIGFETS) were investigated experimentally. The interface state density distribution within the fundamental band gap is less than 1012 cm-2 eV-1 and the DC transistor characteristics are stable, with drain current drift of 2+or-1% for gate voltages between -0.2 and 0.2 V over a time period of 700 s.

High power InGaAs/GaAs laser array

The fabrication and performance characteristics of In0.2Ga0.8As/GaAs gain guided laser arrays emitting near 1 μm are reported. The multiquantum well active region has three wells and is grown by molecular beam epitaxy. The 1 mm long lasers have a broad area threshold current density of 90 A/cm2. The estimated transparency current density per well from the measured threshold current density against cavity length data is 22 A/cm2. The ten-stripe coupled laser arrays have been operated to pulsed output powers of 4 W and CW output power of 1 W.