p-type GaN grown by phase shift epitaxy

Zhong, Mingyu; Roberts, Jeff; Kong, Wei; Brown, April S.; Steckl, A. J.

doi:10.1063/1.4861058

Cited by 6 publications

(2 citation statements)

References 23 publications

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“…During MOCVD growth, the problems associated with Mg doping for higher hole concentrations include: (1) a large volume of crystal defects being introduced by magnesium ion implantation [198]; (2) the low p-type activation of Mg-H into GaN, which can lead to higher resistivities than those with similar hole concentrations [199]; (3) the selfcompensation effect due to the nitrogen vacancy donor (V N ) and its complexes, which determines its resistivity [200], (4) the Mg segregation on threading dislocation, which can lead to degraded crystal quality and defects [194], and (5) Mg diffusion, which can induce an increase in the 2DEG R sh and V TH shifts [201]. To date, several growth techniques have been shown to solve the above problems-such as the defect quasi Fermi level control process [199], chemical potential control [202], metal modulation epitaxy [203], phase shift epitaxy [204], and the use of an AlN interlayer between the p-GaN and AlGaN structures [193]. Based on the contributions of numerous researchers, Dai et al [193] reported that a hole concentration of 1.3 × 10 18 cm −3 with a high activation efficiency of 2.2% was achieved in the p-GaN/AlN/AlGaN structure.…”

Section: P-gan/(in)al(ga)n/gan Structurementioning

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: P-gan/(in)al(ga)n/gan Structurementioning

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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“…The high activation energy leads to a relatively lower hole concentration even though Mg doping concentration is high and hence a low conductivity level according to the equation,

here, σ is the conductivity, q is the electron charge, n is the hole concentration, R is the sheet resistance, N is the sheet hole concentration, and μ is the hole mobility. Following the trace of developing p-GaN [ 14 , 15 , 16 , 17 , 18 , 19 , 20 ], a few approaches have been developed for improving the p-type conductivity of Mg-doped AlGaN, such as the technique of delta-doping [ 15 ]. With metalorganic chemical vapor deposition (MOCVD), the resistivity of a high-Al AlGaN sample could be reduced by using a high V/III ratio and a moderate level of Mg doping [ 21 ].…”

Section: Introductionmentioning

confidence: 99%

Improvement of p-Type AlGaN Conductivity with an Alternating Mg-Doped/Un-Doped AlGaN Layer Structure

Chen

Lin

et al. 2021

Micromachines

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Using molecular beam epitaxy, we prepared seven p-type AlGaN samples of ~25% in Al content, including six samples with Mg-doped/un-doped AlGaN alternating-layer structures of different layer-thickness combinations, for comparing their p-type performances. Lower sheet resistance and higher effective hole mobility are obtained in a layer-structured sample, when compared with the reference sample of uniform Mg doping. The improved p-type performance in a layer-structured sample is attributed to the diffusion of holes generated in an Mg-doped layer into the neighboring un-doped layers, in which hole mobility is significantly higher because of weak ionized impurity scattering. Among the layer-structured samples, that of 6/4 nm in Mg-doped/un-doped thickness results in the lowest sheet resistance (the highest effective hole mobility), which is 4.83 times lower (4.57 times higher) when compared with the sample of uniform doping. The effects of the Mg-doped/un-doped layer structure on p-type performance in AlGaN and GaN are compared.

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Effects of Mg incorporation in cubic GaN films grown by PAMBE near Ga rich conditions

García

Moreno-García

López‐Luna

et al. 2019

Materials Science in Semiconductor Processing

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p-type GaN grown by phase shift epitaxy

Cited by 6 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

Improvement of p-Type AlGaN Conductivity with an Alternating Mg-Doped/Un-Doped AlGaN Layer Structure

Effects of Mg incorporation in cubic GaN films grown by PAMBE near Ga rich conditions

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