Reverse Gate-Current of AlGaN/GaN HFETs: Evidence of Leakage at Mesa Sidewalls

Mojaver, Hassan Rahbardar; Valizadeh, Pouya

doi:10.1109/ted.2016.2529301

Cited by 22 publications

(6 citation statements)

References 23 publications

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“…Consequently, it has been widely accepted by a large number of researchers [213][214][215]. However, such processes may also increase the degradation of device performance-such as I GS and V BD -due to plasma etching damaging the side wall where the mesa is induced [216]. More importantly, the passivation layer is introduced to passivate mesa side walls, which can add an additional leakage path owing to the direct contact of 2DEG with passivation layer, yielding a substantial I GS and non-uniform V BD [217].…”

Section: Device Isolationmentioning

confidence: 99%

GaN-based power high-electron-mobility transistors on Si substrates: from materials to devices

Wu¹,

Xing²,

Li³

et al. 2023

Semicond. Sci. Technol.

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Conventional silicon (Si)-based power devices face physical limitations—such as switching speed and energy efficiency—which can make it difficult to meet the increasing demand for high-power, low-loss, and fast-switching-frequency power devices in power electronic converter systems. Gallium nitride (GaN) is an excellent candidate for next-generation power devices, capable of improving the conversion efficiency of power systems owing to its wide band gap, high mobility, and high electric breakdown field. Apart from their cost effectiveness, GaN-based power high-electron-mobility transistors (HEMTs) on Si substrates exhibit excellent properties—such as low ON-resistance and fast switching—and are used primarily in power electronic applications in the fields of consumer electronics, new energy vehicles, and rail transit, amongst others. During the past decade, GaN-on-Si power HEMTs have made major breakthroughs in the development of GaN-based materials and device fabrication. However, the fabrication of GaN-based HEMTs on Si substrates faces various problems—for example, large lattice and thermal mismatches, as well as ‘melt-back etching’ at high temperatures between GaN and Si, and buffer/surface trapping induced leakage current and current collapse. These problems can lead to difficulties in both material growth and device fabrication. In this review, we focused on the current status and progress of GaN-on-Si power HEMTs in terms of both materials and devices. For the materials, we discuss the epitaxial growth of both a complete multilayer HEMT structure, and each functional layer of a HEMT structure on a Si substrate. For the devices, breakthroughs in critical fabrication technology and the related performances of GaN-based power HEMTs are discussed, and the latest development in GaN-based HEMTs are summarised. Based on recent progress, we speculate on the prospects for further development of GaN-based power HEMTs on Si. This review provides a comprehensive understanding of GaN-based HEMTs on Si, aiming to highlight its development in the fields of microelectronics and integrated circuit technology.

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Section: Device Isolationmentioning

confidence: 99%

GaN-based power high-electron-mobility transistors on Si substrates: from materials to devices

Wu¹,

Xing²,

Li³

et al. 2023

Semicond. Sci. Technol.

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“…Mojaver and Valizadeh [10,[18][19][20] have identified a gate leakage component due to the gate metal in contact with the two-dimensional electron gas (2-DEG) on the side-wall of the mesa. This current flows from the drain/source to the gate metal on the side-wall via the 2-DEG for V GS > V T .…”

Section: Device Structures and Measurementsmentioning

confidence: 99%

“…While following this approach, prior works other than [8,9] have employed one-dimensional theory, and so reached different conclusions about the path and distribution of I G . Thus [10][11][12][13], inferred channel to gate flow distributed uniformly over gate area (path-1 in figure 1(a)). On the other hand [14], inferred surface flow from drain/source to gate concentrated at the gate edges (path-3 in figure 1(a)).…”

Section: Introductionmentioning

confidence: 99%

Extraction of the edge/areal components and path of the reverse gate leakage in a GaN HEMT from measurements

Prasannanjaneyulu¹,

Rawal²,

Karmalkar³

2022

Semicond. Sci. Technol.

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Reverse gate leakage, IG, limits the reliability of GaN HEMTs. We extract the components of IG flowing into the edge and area of the gate from the measured IG versus gate to source voltage, VGS, data of both low and high IG devices. The components are separated by analyzing the change in IG with gate length, LG. We estimate the short and long channel limits of LG for which the IG flows predominantly into the edge and area, respectively. Prior one-dimensional IG models based on the areal field are valid for simulating long channel devices. However, the IG of short channel devices should be modeled using the edge field, and can be reduced by techniques like field plate or high-k passivation which reduce the edge field. Also, we find the measured IG to be independent of the un-gated length, implying that IG flows via the channel rather than surface. Our work dispels any prior misperception of IG being area dominated irrespective of LG and gives the right direction for modelling and control of IG.

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“…Hopping through high-density surface electronic states in AlGaN is only significant for very short gate to drain distances, when its corresponding current approaches the more significant vertical tunneling component of the leakage current [13]. This surface component can be easily controlled through proper passivation.…”

Section: Introductionmentioning

confidence: 99%

DC Gate Leakage Current Model Accounting for Trapping Effects in AlGaN/GaN HEMTs

et al. 2018

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A DC leakage current model accounting for trapping effects under the gate of AlGaN/GaN HEMTs on silicon has been developed. Based on TCAD numerical simulations (with Sentaurus Device), non-local tunneling under the Schottky gate is necessary to reproduce the measured transfer characteristics in a subthreshold regime. Once the trap concentration and distribution are determined in the device, the resulting gate leakage current is modeled making use of Verilog-A, for typical operation regimes.

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Reverse Gate-Current of AlGaN/GaN HFETs: Evidence of Leakage at Mesa Sidewalls

Cited by 22 publications

References 23 publications

GaN-based power high-electron-mobility transistors on Si substrates: from materials to devices

GaN-based power high-electron-mobility transistors on Si substrates: from materials to devices

Extraction of the edge/areal components and path of the reverse gate leakage in a GaN HEMT from measurements

DC Gate Leakage Current Model Accounting for Trapping Effects in AlGaN/GaN HEMTs

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