On the physical operation and optimization of the p-GaN gate in normally-off GaN HEMT devices

Efthymiou, Loizos; Longobardi, Giorgia; Camuso, Gianluca; Chien, Terry; Chen, M; Udrea, F.

doi:10.1063/1.4978690

Cited by 100 publications

(57 citation statements)

References 20 publications

(12 reference statements)

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“…But approaching the doping concentration of 1 × 10 18 cm −3 in the situation starts to be complicated even for doping concentration of the channel layer 2 × 10 17 cm −3 . Ethymiou et al found that for higher doping concentrations, the trend has changed and the threshold voltage starts to decrease. In the capacitance measurement, it is probably connected with a negative differential capacitance occurrence.…”

Section: Resultsmentioning

confidence: 99%

Simulation of Structure Parameters' Influence on the Threshold Voltage of Normally‐Off p‐GaN/AlGaN/GaN Transistors

Osvald

2019

Physica Status Solidi (a)

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The influence of different parameters of p-GaN/AlGaN/GaN structure on a threshold voltage of transistors is studied. The parameters that are varied are the thickness of the p-type GaN layer, its doping concentration, doping concentration of the GaN channel layer, and Schottky barrier height. Increasing the thickness of the p-GaN layer is found to increase the threshold voltage. Also, increasing doping concentration of the p-GaN layer increases the threshold voltage. The doping concentration of the GaN channel layer has the decisive effect on the possibility to use capacitance measurement for the threshold voltage assessment. Simulations show an interesting result of the Schottky barrier height threshold voltage dependence. For higher Schottky barrier height, lower threshold voltage is received, which is connected with the contribution of the negative differential capacitance of the p-GaN layer. This starts to increase for higher positive voltage if the Schottky barrier height is lower.

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Section: Resultsmentioning

confidence: 99%

Simulation of Structure Parameters' Influence on the Threshold Voltage of Normally‐Off p‐GaN/AlGaN/GaN Transistors

Osvald

2019

Physica Status Solidi (a)

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“…Typically, in a normally-off p-GaN/AlGaN/GaN heterostructure the AlGaN barrier layer thickness is in the range of 10–15 nm, while the Al concentration is in the order of 15–20%. Moreover, a high doping level of the p-GaN layer (> 10 18 cm −3 ) is typically required for an efficient depletion of the region at the metal-gate/p-GaN interface [29]. In this sense, one of the key elements to improve the threshold voltage V th for a fixed Mg-concentration of the p-GaN layer is to increase the Mg electrical activation.…”

Section: Normally-off Gan Hemt Technologymentioning

confidence: 99%

“…In fact, the threshold voltage of the device V th is related, among other things, to the metal/p-GaN Schottky barrier height. Several papers in the last years discussed on the influence of metal gate work-function on the electrical behavior of p-GaN gate HEMTs [29,32,33,34,35].…”

Section: Normally-off Gan Hemt Technologymentioning

confidence: 99%

An Overview of Normally-Off GaN-Based High Electron Mobility Transistors

et al. 2019

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Today, the introduction of wide band gap (WBG) semiconductors in power electronics has become mandatory to improve the energy efficiency of devices and modules and to reduce the overall electric power consumption in the world. Due to its excellent properties, gallium nitride (GaN) and related alloys (e.g., AlxGa1−xN) are promising semiconductors for the next generation of high-power and high-frequency devices. However, there are still several technological concerns hindering the complete exploitation of these materials. As an example, high electron mobility transistors (HEMTs) based on AlGaN/GaN heterostructures are inherently normally-on devices. However, normally-off operation is often desired in many power electronics applications. This review paper will give a brief overview on some scientific and technological aspects related to the current normally-off GaN HEMTs technology. A special focus will be put on the p-GaN gate and on the recessed gate hybrid metal insulator semiconductor high electron mobility transistor (MISHEMT), discussing the role of the metal on the p-GaN gate and of the insulator in the recessed MISHEMT region. Finally, the advantages and disadvantages in the processing and performances of the most common technological solutions for normally-off GaN transistors will be summarized.

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“…For example, Fujii et al [151] presented the control of threshold voltage by the variation AlGaN barrier layer thickness and AlN molar fraction. Efthymiou et al [152] investigated effects of the p-GaN doping and gate metal work function on the threshold voltage of devices. Bakeroot et al [153] developed an analytical model for calculation of the threshold voltage for p-GaN HEMTs, they studied the contributions of p-type doping profile, AlN molar fraction of AlGaN layer and AlGaN layer thickness to the threshold voltage.…”

Section: Algan/gan Device Simulationmentioning

confidence: 99%

A Comprehensive Review of Recent Progress on GaN High Electron Mobility Transistors: Devices, Fabrication and Reliability

et al. 2018

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GaN based high electron mobility transistors (HEMTs) have demonstrated extraordinary features in the applications of high power and high frequency devices. In this paper, we review recent progress in AlGaN/GaN HEMTs, including the following sections. First, challenges in device fabrication and optimizations will be discussed. Then, the latest progress in device fabrication technologies will be presented. Finally, some promising device structures from simulation studies will be discussed.

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On the physical operation and optimization of the p-GaN gate in normally-off GaN HEMT devices

Cited by 100 publications

References 20 publications

Simulation of Structure Parameters' Influence on the Threshold Voltage of Normally‐Off p‐GaN/AlGaN/GaN Transistors

Simulation of Structure Parameters' Influence on the Threshold Voltage of Normally‐Off p‐GaN/AlGaN/GaN Transistors

An Overview of Normally-Off GaN-Based High Electron Mobility Transistors

A Comprehensive Review of Recent Progress on GaN High Electron Mobility Transistors: Devices, Fabrication and Reliability

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