- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Electronic band alignment in AlGaN/GaN high electron-mobility transistors investigated using scanning photocurrent microscopy
摘要： The band alignment in AlGaN/GaN HEMT devices was investigated using scanning photocurrent microscopy (SPCM) with UV and visible light sources. The polarity of the SPCM on the conduction channel exhibited a switching behavior from p-type to n-type response as the gate bias was increased. The ?at-band voltage, which was higher than the DC turn-on voltage, indicates that an ohmic metallic contact was formed for electron transport. We obtained the band o?set between the conduction band and the metal Fermi level, which yielded a value of 2.1 eV on average.
关键词： SPCM,GaN,2DEG,HEMT
更新于2025-09-23 15:23:52
-
An improved 2D–3D model for charge transport based on the maximum entropy principle
摘要： To study the electron transport in a some tens of nanometers long channel of a metal oxide ?eld effect transistor, in order to reduce the computational cost of simulations, it can be convenient to divide the electrons into a 2D and a 3D population. Near the silicon/oxide interface the two populations coexist, while in the remaining part of the device only the 3D component needs to be considered because quantum effects are negligible there. The major issue is the description of the scattering mechanisms between the 2D and the 3D electron populations, due to interactions of electrons with nonpolar optical phonons and interface modes. Here, we propose a rigorous treatment of these collisions based on an approach similar to that used in Fischetti and Laux (Phys Rev B 48:2244–2274, 1993), in the context of a Monte Carlo simulation. We also consider all the other main scatterings, which are those with acoustic phonons, surface roughness, and impurities.
关键词： Semiconductors,2DEG,Quantum con?nement,Maximum entropy principle,Hydrodynamical models
更新于2025-09-23 15:22:29
-
Evaluation of Low-Temperature Saturation Velocity in β -(Al?Ga???)?O?/Ga?O? Modulation-Doped Field-Effect Transistors
摘要： We report on the high-field transport characteristics and saturation velocity in a modulation-doped β-(AlxGa1?x)2O3/Ga2O3 heterostructure. The formation of a 2-D electron gas (2DEG) in the modulation-doped structure was confirmed from the Hall measurements, and the 2DEG channel mobility increased from 143 cm2/V·s at room temperature to 1520 cm2/V·s at 50 K. The high electron mobility at 50 K made it feasible to achieve velocity saturation inside the channel. The saturation velocity was estimated based on both pulsed current–voltage measurements and small-signal radio frequency (RF) measurements. The measured velocity–field profile suggested a saturation velocity above 1.1 × 107 cm/s at 50 K. The small-signal RF characteristics were measured for the fabricated modulation-doped field-effect transistors with a Pt-based Schottky contact. The current gain cutoff frequency (ft) and maximum oscillation frequency (fmax) showed significant increases from 4.0/11.8 GHz at room temperature to 17.4/40.8 GHz at 50 K for the device with gate length of LG = 0.61 μm. The analysis of the low temperature ft based on device simulations indicated a peak velocity of 1.2 × 107 cm/s. The three-terminal off-state breakdown measurement further suggested an average breakdown field of 3.22 MV/cm. The high saturation velocity and high breakdown field in β-Ga2O3 make it a promising candidate for high-power and high-frequency device applications.
关键词： mobility,β-Ga2O3,modulation-doped field-effect transistor (MODFET),2-D electron gas (2DEG),saturation velocity,high breakdown field
更新于2025-09-23 15:22:29
-
Selective Area Deposition of Hot Filament CVD Diamond on 100 mm MOCVD Grown AlGaN/GaN Wafers
摘要： A new technique is reported for selective growth of polycrystalline diamond by hot filament chemical vapor deposition (HFCVD) on AlGaN/GaN-on-Si (111) wafers without degradation of the underlying layers. Selective diamond seeding is accomplished by dispersing nano-diamond seeds in photoresist and patterned lithographically prior to HFCVD growth. A thin layer of plasma enhanced CVD SiNx, deposited prior to seeding and diamond deposition, was found to be essential to protect the AlGaN/GaN wafer. Methane concentration of 3.0% was used to achieve increased diamond growth rate and faster surface coverage. Excellent selectivity and minimal AlGaN surface damage were achieved due to the protective layer and faster surface coverage with increased methane concentration. Damage mitigation was confirmed by comparison of atomic force microscopy, x-ray diffraction, and Raman spectroscopy, each conducted before and after diamond deposition, and by SEM images of the final structures.
关键词： 2DEG,Reciprocal space mapping,III-Nitride,SiNx,Selective area deposition,CVD diamond,Photolithography,GaN decomposition
更新于2025-09-23 15:22:29
-
[Lecture Notes in Electrical Engineering] Microelectronics, Electromagnetics and Telecommunications Volume 521 (Proceedings of the Fourth ICMEET 2018) || Impact of p-GaN Gate Length on Performance of AlGaN/GaN Normally-off HEMT Devices
摘要： In this work, we have studied the effect of variation in length of GaN gate with p-type doping concentration on the DC performances of AlGaN/GaN normally-off HEMT using 2D Atlas TCAD simulator. A comprehensive simulation is undertaken on the proposed device to examine different performance parameters such as drain current, transconductance factor, energy band diagram, and surface potential with respect to change in p-type GaN gate lengths. The gate lengths are varied from 60 to 90 nm, and it is noticed from the simulation results that with a decrease in gate length the drain current increases and transconductance increases. A proper optimization of gate length is indispensable to preserve the normally-off mode operation and at the same time enhancing certain performance parameters.
关键词： 2DEG,AlGaN/GaN,p-GaN gate,ATLAS
更新于2025-09-23 15:21:21
-
Ultrahigh-Speed Mid-Infrared Photodetectors With 2-D Electron Gas in a CdTe/PbTe Heterojunction
摘要： A CdTe/PbTe heterojunction (HJ) yields two-dimensional electron gas (2DEG) with a high electron density and mobility. Ultrahigh-speed and room-temperature operating mid-infrared photodetectors are developed with the 2DEG. The photoresponse of the detectors originates from the intrinsic response of PbTe by virtue of the conduction-band and valence-band alignment of the HJ. The extremely short rise and decay photoresponse time demonstrate a major advantage of the 2DEG. At λ = 3.0 μm and a bias voltage of 100 mV, the responsivity and detectivity reach 0.94 A/W and 2 × 1010 Jones, respectively. The excellent performance of the detectors renders promising applications in novel mid-infrared frequency detection systems.
关键词： two-dimensional electron gas (2DEG),room-temperature (RT) operation,ultrahigh-speed response,Detectivity,mid-infrared detector
更新于2025-09-23 15:21:01
-
Correlation Between Two-Dimensional Electron Gas Mobility and Crystal Quality in AlGaN/GaN High-Electron-Mobility Transistor Structure Grown on 4H-SiC
摘要： We investigated the correlation between the crystal quality and two-dimensional electron gas (2DEG) mobility of an AlGaN/GaN high-electron-mobility transistor (HEMT) structure grown by metal-organic chemical vapor deposition. For the structure with an AlN nucleation layer grown at 1100 °C, the 2DEG mobility and sheet carrier density were 1627 cm2/V·s and 3.23 × 1013 cm?2, respectively, at room temperature. Further, it was confirmed that the edge dislocation density of the GaN buffer layer was related to the 2DEG mobility and sheet carrier density in the AlGaN/GaN HEMT.
关键词： MOCVD,2DEG,Mobility,AlGaN/GaN HEMT,Carrier Density,Edge and Screw Dislocation
更新于2025-09-19 17:15:36
-
Analytical Study of Electron Mobility in Hemts Algan/Gan
摘要： The hetero junctions GaN based offer an excellent potential for power applications at high frequency. This is due to the important energy of the bandgap and high saturation velocity of electrons. The high mobility transistors (HEMT - High Electron Mobility Transistor) are based on the heterojunction AlGaN/GaN. Our work is the subject of an analytical study of the carrier mobility HEMTs AlGaN/GaN calculating Ionized impurities scattering, Residual impurities scattering, Interface roughness scattering, Alloy disorder scattering, dislocations scattering, Phonons and Dipoles taking into account the impact of technological parameters (doping, aluminium content) and geometric (thickness barrier, interface roughness). The results allowed us to take account of the variation of carrier density in the wells of 2D electronic gas.
关键词： HEMT,Mobility,Scattering mechanism,AlGaN/GaN heterojunction,2DEG
更新于2025-09-10 09:29:36
-
Analytical Gate Capacitance Models for Large-Signal Compact Model of AlGaN/GaN HEMTs
摘要： In this paper, analytical gate capacitance models for a large-signal compact model of AlGaN/GaN high-electron mobility transistors are proposed. Different from the MOSFET devices, different depletion regions on either side of the gate are fully considered for high-voltage GaN devices. The depletion regions are bias-dependent to implement the capacitance models into the large-signal compact model. A transfer function is proposed to characterize the switching behavior of the capacitances between on- and off-states, which is essential to describe all the states of a device, for example, operating at Class-B. Different from previous works, the current saturation phenomenon is taken into account in determining the intrinsic capacitances which are induced by nonstatic channel charge. The capacitance models can be easily implemented into the virtual-source-based model to accurately predict the S-parameters and large-signal output characteristics.
关键词： intrinsic capacitances,2-D electron gas (2DEG)-electrode fringing capacitances,AlGaN/GaN high-electron mobility transistors (HEMTs),large-signal compact model
更新于2025-09-09 09:28:46
-
Enhancement of electrons confinement in AlGaN/AlN/GaN heterostructure using BGaN buffer with a small B-content
摘要： Since the small lattice constant a of wurtzite BGaN alloy and the good insulating property of its epitaxial layer, the use of the BGaN with a small B-content (0.005~0.02) as a buffer has potential to be a back-barrier for GaN high-electron mobility transistors (HEMTs). This paper presents an improved BGaN back-barrier HEMT structure (AlGaN/AlN/GaN/BGaN buffer) that does not create parasitic electron channel. The energy-band profile and carrier distribution of the BGaN buffer structure are studied by one-dimensional self-consistent simulation. The results show that the BGaN buffer with a very small B-content can provide a sufficient back-barrier to enhance electrons confinement, the principle of which is similar to the formation of back-barrier of AlGaN buffer. When the channel increases to a certain thickness, the low-density two-dimensional hole gas (2DHG) can even be induced at the GaN/BGaN interface by increasing the B-content from 0 to 0.02. Once the 2DHG is formed, continued increase in B-content would result in higher density 2DHG, while the effect on the energy-band profile, electrons confinement, and two-dimensional electron gas (2DEG) density becomes less pronounced.
关键词： HEMT,Back barrier,2DEG,2DHG,AlGaN/GaN,BGaN
更新于2025-09-04 15:30:14