A New Study on the Temperature and Bias Dependence of the Kink Effects in S22 and h21 for the GaN HEMT Technology

The aim of this feature article is to provide a deep insight into the origin of the kink effects affecting the output reflection coefficient (S22) and the short-circuit current-gain (h21) of solid-state electronic devices. To gain a clear and comprehensive understanding of how these anomalous phenomena impact device performance, the kink effects in S22 and h21 are thoroughly analyzed over a broad range of bias and temperature conditions. The analysis is accomplished using high-frequency scattering (S-) parameters measured on a gallium-nitride (GaN) high electron-mobility transistor (HEMT). The experiments show that the kink effects might become more or less severe depending on the bias and temperature conditions. By using a GaN HEMT equivalent-circuit model, the experimental results are analyzed and interpreted in terms of the circuit elements to investigate the origin of the kink effects and their dependence on the operating condition. This empirical analysis provides valuable information, simply achievable by conventional instrumentation, that can be used not only by GaN foundries to optimize the technology processes and, as a consequence, device performance, but also by designers that need to face out with the pronounced kink effects of this amazing technology.

Download Full-text

Effect of GaN Cap Layer on the Electrical Properties of AlGaN/GaN HEMT

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.217-219.2393 ◽

2012 ◽

Vol 217-219 ◽

pp. 2393-2396 ◽

Cited By ~ 6

Author(s):

Han Guo ◽

Wu Tang ◽

Wei Zhou ◽

Chi Ming Li

Keyword(s):

Electrical Properties ◽

Doping Concentration ◽

Cutoff Frequency ◽

High Electron Mobility Transistor ◽

Current Gain ◽

High Electron ◽

Saturation Current ◽

Gan Hemt ◽

Cap Layer ◽

Dimensional Electron Gas

The electrical properties of AlGaN/GaN heterojunction high electron mobility transistor (HEMT) are simulated by using sentaurus software. This paper compares two structures, the HEMT with GaN cap layer and the HEMT without GaN cap layer. The sentaurus software simulates the DC and AC characteristics of the two AlGaN/GaN HEMT structures. The HEMT with GaN cap layer can increase the maximum transconductance gm from 177ms/mm to 399ms/mm when the doping concentration of the cap layer is 3×1018cm-3 compared with the other structure under the same conditions. The simulation results indicate that the HEMT with cap layer can increase maximum transconductance gm, saturation current Ids, current-gain cutoff frequency fT, maximum oscillation frequency fmax and reduce the series resistance of the drain to source compared with the HEMT without GaN cap layer. The large Ids of the HEMT with cap layer is attributed to the increase of the concentration of two dimensional electron gas (2DEG). Moreover, the change of the doping concentration of the cap layer will affect the gm and Ids.

Download Full-text

High Power Normally-OFF GaN/AlGaN HEMT with Regrown p Type GaN

Energies ◽

10.3390/en14196098 ◽

2021 ◽

Vol 14 (19) ◽

pp. 6098

Author(s):

Gwen Rolland ◽

Christophe Rodriguez ◽

Guillaume Gommé ◽

Abderrahim Boucherif ◽

Ahmed Chakroun ◽

...

Keyword(s):

High Electron Mobility Transistor ◽

Device Performance ◽

High Electron ◽

Chemical Beam Epitaxy ◽

High Electron Mobility ◽

Device Failure ◽

Gan Hemt ◽

Silvaco Atlas ◽

P Type ◽

The Impact

In this paper is presented a Normally-OFF GaN HEMT (High Electron Mobility Transistor) device using p-doped GaN barrier layer regrown by CBE (Chemical Beam Epitaxy). The impact of the p doping on the device performance is investigated using TCAD simulator (Silvaco/Atlas). With 4E17 cm−3 p doping, a Vth of 1.5 V is achieved. Four terminal breakdowns of the fabricated device are investigated, and the origin of the device failure is identified.

Download Full-text

Electrical modeling of packaged GaN HEMT dedicated to internal power matching in S-band

International Journal of Microwave and Wireless Technologies ◽

10.1017/s1759078712000530 ◽

2012 ◽

Vol 4 (5) ◽

pp. 495-503 ◽

Cited By ~ 2

Author(s):

Jérôme Chéron ◽

Michel Campovecchio ◽

Denis Barataud ◽

Tibault Reveyrand ◽

Michel Stanislawiak ◽

...

Keyword(s):

High Efficiency ◽

Extraction Procedure ◽

Equivalent Circuit Model ◽

High Electron Mobility Transistor ◽

Oxide Semiconductor ◽

High Electron ◽

Electrical Modeling ◽

Power Matching ◽

Gan Hemt ◽

Gan Hemts

The electrical modeling of power packages is a major issue for designers of high-efficiency hybrid power amplifiers. This paper reports the synthesis and the modeling of a packaged Gallium nitride (GaN) High electron mobility transistor (HEMT) associating a nonlinear model of the GaN HEMT die with an equivalent circuit model of the package. The extraction procedure is based on multi-bias S-parameter measurements of both packaged and unpackaged (on-wafer) configurations. Two different designs of 20 W packaged GaN HEMTs illustrate the modeling approach that is validated by time-domain load-pull measurements in S-band. The advantage of the electrical modeling dedicated to packaged GaN HEMTs is to enable a die-package co-design for power matching. Internal matching elements such as Metal oxide semiconductor (MOS) capacitors, Monolithic microwave integrated circuits (MMICs), and bond wires can be separately modeled to ensure an efficient optimization of the package for high power Radio frequency (RF) applications.

Download Full-text

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

Micromachines ◽

10.3390/mi12070751 ◽

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.

Download Full-text

Closed-Surface Multifunctional Antireflective Coating Made from SiO2 with TiO2 Nanocomposites

Materials ◽

10.3390/ma14061367 ◽

2021 ◽

Vol 14 (6) ◽

pp. 1367

Author(s):

Zhiqiu Guo ◽

Ze Zhu ◽

Ya Liu ◽

Changjun Wu ◽

Hao Tu ◽

...

Keyword(s):

Electron Microscopy ◽

Short Circuit ◽

Sol Gel ◽

Short Circuit Current ◽

Closed Surface ◽

Chain Structure ◽

High Photocatalytic Activity ◽

Current Gain ◽

Antireflective Coating ◽

Reliability And Robustness

An SiO2-TiO2 closed-surface antireflective coating was fabricated by the one-dipping method. TiO2 nanoparticles were mixed with a nanocomposited silica sol, which was composed of acid-catalyzed nanosilica networks and silica hollow nanospheres (HNs). The microstructure of the sol-gel was characterized by transmission electron microscopy. The silica HNs were approximately 40–50 nm in diameter with a shell thickness of approximately 8–10 nm. The branched-chain structure resulting from acidic hydrolysis grew on these silica HNs, and TiO2 was distributed inside this network. The surface morphology of the coating was measured by field emission scanning electron microscopy and atomic force microscopy. After optimization, transmittance of up to 94.03% was obtained on photovoltaic (PV) glass with a single side coated by this antireflective coating, whose refractive index was around 1.30. The short-circuit current gain of PV module was around 2.14–2.32%, as shown by the current-voltage (IV) curve measurements and external quantum efficiency (EQE) tests. This thin film also exhibited high photocatalytic activity. Due to the lack of voids on its surface, the antireflective coating in this study possessed excellent long-term reliability and robustness in both high-moisture and high-temperature environments. Combined with its self-cleaning function, this antireflective coating has great potential to be implemented in windows and photovoltaic modules.

Download Full-text

Performance Enhancement of AlGaN/GaN HEMT by Optimization of Device Parameters Considering Nanometer Barrier Layer Thickness

International Journal of Nanoscience ◽

10.1142/s0219581x20500118 ◽

2020 ◽

Vol 19 (06) ◽

pp. 2050011

Author(s):

Yogesh Kumar Verma ◽

Varun Mishra ◽

Santosh Kumar Gupta

Keyword(s):

Performance Enhancement ◽

High Electron Mobility Transistor ◽

High Electron ◽

Barrier Layer Thickness ◽

Gan Hemt ◽

Transfer Characteristics ◽

Strong Inversion ◽

Present Design ◽

Device Geometry ◽

Dimensional Electron Gas

The two-dimensional electron gas (2DEG) at the heterointerface of AlGaN and GaN is a complicated transcendental function of gate voltage, so an analytical charge control model for AlGaN/GaN high electron mobility transistor (HEMT) is presented accounting for all the three regions of operation (i.e., sub-threshold, moderate, and strong-inversion region). In addition to it, the performance of AlGaN/GaN HEMT is highly dependent on the device geometry. Therefore, to get the optimum performance of the device it is advisable to optimize the parameters governing the device geometry. Accordingly, the output and transfer characteristics, threshold voltage, ON current, OFF current, and transconductance are calculated using numerical computations. The present design is tested to calculate the voltage transfer characteristics (VTC) and transient characteristics of the invertor circuit, after the optimization of the device parameters.

Download Full-text

A differential extended gate-AlGaN/GaN HEMT sensor for real-time detection of ionic pollutants

Analytical Methods ◽

10.1039/c9ay01019j ◽

2019 ◽

Vol 11 (31) ◽

pp. 3981-3986 ◽

Cited By ~ 2

Author(s):

Lei Zhao ◽

Xinsheng Liu ◽

Bin Miao ◽

Zhiqi Gu ◽

Jin Wang ◽

...

Keyword(s):

Real Time ◽

Electron Mobility ◽

High Electron Mobility Transistor ◽

High Electron ◽

High Electron Mobility ◽

Gan Hemt ◽

Real Time Detection

In this study, we propose a differential extended gate (DEG)-AlGaN/GaN high electron mobility transistor (HEMT) sensor to detect ionic pollutants in solution.

Download Full-text

A Dynamic Response of a Module/Array Simulator Using I-V Magnifier Circuit of a PN Photo-Sensor

Solar Energy ◽

10.1115/isec2003-44061 ◽

2003 ◽

Cited By ~ 3

Author(s):

Hiroshi Nagayoshi

Keyword(s):

Dynamic Response ◽

Personal Computer ◽

Short Circuit ◽

Short Circuit Current ◽

Maximum Power ◽

Current Gain ◽

Led Driver ◽

Photo Sensor ◽

Driver Circuit ◽

Basic Characteristics

Basic characteristics and dynamic response of a 30W module/array simulator using PV I-V magnifier circuit was studied. It was confirmed that each gain of voltage and current was independently adjustable using feedback control of current signal. Simulator circuit output power is controlled by LED irradiation light which works as an irradiation of sun light to real PV modules. Maximum power of the circuit depends on maximum power of the power amplifier used in the circuit. A photo-current of pn photo-sensor was some micro ampere hence the current gain of the simulator needed more than 50dB. The voltage gain was not more than 3dB because a multi junction pn photo-sensor was used. To control the simulator circuit by personal computer, an LED driver circuit was added. A fill factor was also easily changeable by change of shunt resistor connected with pn photo-sensor in parallel. A dynamic response of short circuit current was measured and confirmed that the circuit has enough response ability to apply the MPPT evaluation. A grand line of each module is isolated, hence any topology of connections is available. This circuit simplifies the control system and makes it easy to handle multi simulator units by one personal computer. This system is suitable for the evaluation of multi inverter system.

Download Full-text

The Building of Offshore Facilities Power System’s Equivalent Circuit Model

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.219-220.648 ◽

2011 ◽

Vol 219-220 ◽

pp. 648-651

Author(s):

Hong Zhang ◽

Xu Hui Ma ◽

Xiu Ye Yin

Keyword(s):

Power System ◽

Equivalent Circuit ◽

System Development ◽

Short Circuit ◽

Recursive Algorithm ◽

Equivalent Circuit Model ◽

Short Circuit Current ◽

Circuit Model ◽

Calculation Process ◽

Current Calculation

With the development of technology, the power system of offshore facilities (for short: power system) is increasingly complex, short-circuit current calculation process also becomes more complex. The simple recursive algorithm can not meet the requirements of short-circuit current calculation in complex power system. The paper, basing on the principle of short-circuit current calculation, taking modeling ideas, created an equivalent circuit model of power system for short-circuit current calculation. The equivalent circuit model can be used to simplify the progress of calculation and meet the needs of the power system development.

Download Full-text