scholarly journals Review of Recent Progress on Vertical GaN-Based PN Diodes

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Taofei Pu ◽  
Usman Younis ◽  
Hsien-Chin Chiu ◽  
Ke Xu ◽  
Hao-Chung Kuo ◽  
...  
Keyword(s):  
Wide Bandgap ◽  
Structure Design ◽  
High Electron ◽  
Crowding Effect ◽  
Device Structure ◽  
Electrical Field ◽  
Edge Termination ◽  
Saturation Velocity ◽  
Silicon Carbon ◽  
Great Performance

AbstractAs a representative wide bandgap semiconductor material, gallium nitride (GaN) has attracted increasing attention because of its superior material properties (e.g., high electron mobility, high electron saturation velocity, and critical electric field). Vertical GaN devices have been investigated, are regarded as one of the most promising candidates for power electronics application, and are characterized by the capacity for high voltage, high current, and high breakdown voltage. Among those devices, vertical GaN-based PN junction diode (PND) has been considerably investigated and shows great performance progress on the basis of high epitaxy quality and device structure design. However, its device epitaxy quality requires further improvement. In terms of device electric performance, the electrical field crowding effect at the device edge is an urgent issue, which results in premature breakdown and limits the releasing superiorities of the GaN material, but is currently alleviated by edge termination. This review emphasizes the advances in material epitaxial growth and edge terminal techniques, followed by the exploration of the current GaN developments and potential advantages over silicon carbon (SiC) for materials and devices, the differences between GaN Schottky barrier diodes (SBDs) and PNDs as regards mechanisms and features, and the advantages of vertical devices over their lateral counterparts. Then, the review provides an outlook and reveals the design trend of vertical GaN PND utilized for a power system, including with an inchoate vertical GaN PND.

Ultra-Wide Bandgap AlxGa1-xN Channel Transistors

2019 ◽  
Vol 28 (01n02) ◽  
pp. 1940009 ◽  
Author(s):  
Towhidur Razzak ◽  
Siddharth Rajan ◽  
Andrew Armstrong
Keyword(s):  
Current Density ◽  
High Current Density ◽  
Cutoff Frequency ◽  
Wide Bandgap ◽  
Current Gain ◽  
Breakdown Field ◽  
High Electron ◽  
Saturation Velocity ◽  
Rf Devices ◽  
Performance Results

High Al-composition AlxGa1-xN, an emerging class of materials, is gaining significant traction due to its high critical breakdown electric field exceeding that of GaN and high electron saturation velocity that is comparable to GaN. High Al-composition AlxGa1-xN holds promise for applications such as highly scaled next generation RF devices and power devices. However, significant strides remain to be made before AlxGa1-xN can take a share of the limelight. Encouraging progress has been made in recent years, including multiple reports of RF operation of AlxGa1-xN channel transistors with reported unity current gain cutoff frequency as high as 40 GHz, high current density devices with the maximum reported current density exceeding 600 mA/mm and reports of breakdown fields in lateral transistors that are almost 3× the reported breakdown field for GaN channel devices of similar dimensions. This paper focuses on the lateral devices demonstrated thus far and discusses breakthrough performance results achieved for AlxGa1-xN channel transistors together with the key challenges that are yet to be properly addressed. The paper starts with a discussion of contact formation to AlxGa1-xN films – the key difficulty of fabricating AlxGa1-xN transistors. This is followed by a discussion of the types of devices that are typically used. This is followed up with a discussion of the approach required to make high quality devices with AlxGa1-xN as a template together with some recent result highlights.

scholarly journals Physics-Based TCAD Simulation and Calibration of 600 V GaN/AlGaN/GaN Device Characteristics and Analysis of Interface Traps

Micromachines ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 751
Author(s):  
Yu-Lin Song ◽  
Manoj Kumar Reddy ◽  
Luh-Maan Chang ◽  
Gene Sheu
Keyword(s):  
Conduction Band ◽  
Computer Aided Design ◽  
Measurement Data ◽  
High Electron Mobility Transistor ◽  
High Electron ◽  
Device Structure ◽  
Gan Hemt ◽  
Fixed Charges ◽  
Vertical Electric Field ◽  
Aided Design

This study proposes an analysis of the physics-based TCAD (Technology Computer-Aided Design) simulation procedure for GaN/AlGaN/GaN HEMT (High Electron Mobility Transistor) device structures grown on Si (111) substrate which is calibrated against measurement data. The presence of traps and activation energies in the device structure will impact the performance of a device, the source of traps and position of traps in the device remains as a complex exercise until today. The key parameters for the precise tuning of threshold voltage (Vth) in GaN transistors are the control of the positive fixed charges −5 × 1012 cm−2, donor-like traps −3 × 1013 cm−2 at the nitride/GaN interfaces, the energy of the donor-like traps 1.42 eV below the conduction band and the acceptor traps activation energy in the AlGaN layer and buffer regions with 0.59 eV below the conduction band. Hence in this paper, the sensitivity of the trap mechanisms in GaN/AlGaN/GaN HEMT transistors, understanding the absolute vertical electric field distribution, electron density and the physical characteristics of the device has been investigated and the results are in good agreement with GaN experimental data.

Performance Boost Using a New Device Structure Design for SOI MOSFETs Beyond 25nm Node

2019 ◽  
Vol 11 (6) ◽  
pp. 349-355 ◽  
Author(s):  
Weitao Cheng ◽  
Akinobu Teramoto ◽  
Tadahiro Ohmi
Keyword(s):  
Structure Design ◽  
Device Structure ◽  
New Device

Analysis of Thermal Properties of Power Multifinger HEMT Devices

2018 ◽  
Author(s):  
Aleš Chvála ◽  
Robert Szobolovszký ◽  
Jaroslav Kováč ◽  
Martin Florovič ◽  
Juraj Marek ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Thermal Management ◽  
High Electron Mobility Transistor ◽  
Structure Design ◽  
High Electron ◽  
Design And Optimization ◽  
Chip Temperature ◽  
Materials Used ◽  
On Chip ◽  
Measurement Approach

In this paper, several methods suitable for real time on-chip temperature measurements of power AlGaN/GaN based high-electron mobility transistor (HEMT) grown on SiC substrate are presented. The measurement of temperature distribution on HEMT surface using Raman spectroscopy is presented. We have deployed a temperature measurement approach utilizing electrical I-V characteristics of the neighboring Schottky diode under different dissipated power of the transistor heat source. These methods are verified by measurements with micro thermistors. The results show that these methods have a potential for HEMT analysis in thermal management. The features and limitations of the proposed methods are discussed. The thermal parameters of materials used in the device are extracted from temperature distribution in the structure with the support of 3-D device thermal simulation. The thermal analysis of the multifinger power HEMT is performed. The effects of the structure design and fabrication processes from semiconductor layers, metallization, and packaging up to cooling solutions are investigated. The analysis of thermal behavior can help during design and optimization of power HEMT.

Wide-bandgap nanocrystalline silicon-carbon alloys for photovoltaic applications

2018 ◽  
Vol 182 ◽  
pp. 220-227 ◽  
Author(s):  
Jun-Sik Cho ◽  
Eunseok Jang ◽  
Dongmin Lim ◽  
Seungkyu Ahn ◽  
Jinsu Yoo ◽  
...  
Keyword(s):  
Nanocrystalline Silicon ◽  
Wide Bandgap ◽  
Silicon Carbon ◽  
Photovoltaic Applications

The proton flux influence on electrical characteristics of a dual-channel hemt based on GaAs

Doklady BGUIR ◽  
2022 ◽  
Vol 19 (8) ◽  
pp. 81-86
Author(s):  
I. Yu. Lovshenko ◽  
A. Yu. Voronov ◽  
P. S. Roshchenko ◽  
R. E. Ternov ◽  
Ya. D. Galkin ◽  
...  
Keyword(s):  
Field Effect ◽  
Proton Energy ◽  
Field Effect Transistor ◽  
Drain Current ◽  
Proton Flux ◽  
High Electron ◽  
Electrical Characteristics ◽  
Device Structure ◽  
Dual Channel ◽  
Effect Transistor

The results of the simulation the influence of the proton flux on the electrical characteristics of the device structure of dual-channel high electron mobility field effect transistor based on GaAs are presented. The dependences of the drain current ID and cut-off voltage on the fluence value and proton energy, as well as on the ambient temperature are shown.

Structure design and performance of photomultiplication-type organic photodetectors based on an aggregation-induced emission material

Nanoscale ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 2648-2656 ◽  
Author(s):  
Dechao Guo ◽  
Zeng Xu ◽  
Dezhi Yang ◽  
Dongge Ma ◽  
Benzhong Tang ◽  
...  
Keyword(s):  
High Performance ◽  
Structure Design ◽  
Device Structure ◽  
Aggregation Induced Emission ◽  
And Performance ◽  
Organic Photodetectors

High performance photomultiplication-type organic photodetectors based on an AIE material were successfully fabricated by designing a device structure.

scholarly journals Photoluminescence Studies of GaN and AlGaN Layers Under Hydrostatic Pressure

1995 ◽  
Vol 378 ◽  
Author(s):  
C. Wetzel ◽  
W. Walukiewicz ◽  
E. E. Haller ◽  
H. Amano ◽  
I. Akasaki
Keyword(s):  
Hydrostatic Pressure ◽  
Energy Levels ◽  
Wide Bandgap ◽  
High Electron ◽  
Valence Band Edge ◽  
Native Defects ◽  
Free Carriers ◽  
High Electron Concentration ◽  
Localized Defects ◽  
Photoluminescence Studies

AbstractWide bandgap GaN very often shows a high electron concentration. Although several impurities such as O and Si have been identified, the concentration is not high enough to account for the number of free carriers. As a consequence native defects namely the nitrogen vacancies are widely considered to be present at high densities. Several calculations predict different energy levels of this strongly localized defect. We present photoluminescence experiments of wurtzite GaN and AlGaN layers under large hydrostatic pressure to search for localized defects within the questionable energy range of 3 .0 to 3 .8 eV above the valence band edge.

Recent Reliability Progress of GaN HEMT Power Amplifiers

2012 ◽  
Vol 1432 ◽  
Author(s):  
Toshihiro Ohki ◽  
Masahito Kanamura ◽  
Yoichi Kamada ◽  
Kozo Makiyama ◽  
Yusuke Inoue ◽  
...  
Keyword(s):  
High Efficiency ◽  
High Electron Mobility Transistors ◽  
High Electron ◽  
Device Structure ◽  
Passivation Film ◽  
Electron Mobility Transistors ◽  
Current Collapse ◽  
Specific Device ◽  
Gan Hemts ◽  
A Current

ABSTRACTIn this paper, we describe highly reliable GaN high electron mobility transistors (HEMTs) for high-power and high-efficiency amplifiers. First, we present the reliability mechanisms and progress on the previously reported GaN HEMTs. Next, we introduce our specific device structure of GaN HEMTs for improving reliability. An n-GaN cap and optimized buffer layer were used to suppress the trap-related phenomena, such as a current collapse. Gate edge oxidation is effective for reducing the gate leakage current. A Ta-based barrier metal was inserted between an ohmic electrode and interconnection metal for preventing increase in contact resistance. SiN of passivation film was optimized for reducing the current collapse of short-gatelength HEMTs.

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