Mechanism of Ti/Al/Ni/Au ohmic contacts to AlGaN/GaN heterostructures via laser annealing

Hou, Mingchen; Xie, Gang; Sheng, Kuang

doi:10.1088/1674-1056/28/3/037302

Cited by 4 publications

(3 citation statements)

References 30 publications

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“…[1] Therefore, twodimensional (2D) vertically stacked vdW HSs have drawn the attention of many researchers because of their tunable band gaps and thicknesses of several atomic layers. [2] For example, MoS 2 -ZnO, [3] MoS 2 -WSe 2 , [4] BP-BN, [5] MoSe 2graphene, [6] and AlGaN-GaN [7] have provided novel material platforms to explore a range of innovative applications, including ultrathin photodetectors, [8] solar cells, [9] and tunneling transistor-based memory devices. [10] However, the application of these 2D materials is enabled by their outstanding physical properties.…”

Section: Introductionmentioning

confidence: 99%

Electronic and optical properties of GaN–MoS₂ heterostructure from first-principles calculations*

et al. 2019

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Heterostructures (HSs) have attracted significant attention because of their interlayer van der Waals interactions. The electronic structures and optical properties of stacked GaN–MoS2 HSs under strain have been explored in this work using density functional theory. The results indicate that the direct band gap (1.95 eV) of the GaN–MoS2 HS is lower than the individual band gaps of both the GaN layer (3.48 eV) and the MoS2 layer (2.03 eV) based on HSE06 hybrid functional calculations. Specifically, the GaN–MoS2 HS is a typical type-II band HS semiconductor that provides an effective approach to enhance the charge separation efficiency for improved photocatalytic degradation activity and water splitting efficiency. Under tensile or compressive strain, the direct band gap of the GaN–MoS2 HS undergoes redshifts. Additionally, the GaN–MoS2 HS maintains its direct band gap semiconductor behavior even when the tensile or compressive strain reaches 5% or -5%. Therefore, the results reported above can be used to expand the application of GaN–MoS2 HSs to photovoltaic cells and photocatalysts.

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Section: Introductionmentioning

confidence: 99%

Electronic and optical properties of GaN–MoS₂ heterostructure from first-principles calculations*

et al. 2019

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“…The wafer is not damaged during the LA period due to the larger energy bandgap of GaN than LA photon energy. By applying a wavelength of 532 nm, 20 ns of a pulse duration, 100 kHz of pulse frequency, and energy density up to 2.99 J/cm 2 , the achieved R C is 2.18 Ω•mm [95]. The ohmic contact formation mechanism by LA has been studied and proposed.…”

Section: Methodsmentioning

confidence: 99%

Process of Au-Free Source/Drain Ohmic Contact to AlGaN/GaN HEMT

Zhang

Miao

et al. 2022

Crystals

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AlGaN/GaN high electron mobility transistors (HEMTs) are regarded as promising candidates for a 5G communication system, which demands higher frequency and power. Source/drain ohmic contact is one of the key fabrication processes crucial to the device performance. Firstly, Au-contained metal stacks combined with RTA high-temperature ohmic contact schemes were presented and analyzed, including process conditions and contact formation mechanisms. Considering the issues with the Au-contained technique, the overview of a sequence of Au-free schemes is given and comprehensively discussed. In addition, in order to solve various problems caused by high-temperature conditions, novel annealing techniques including microwave annealing (MWA) and laser annealing (LA) were proposed to form Au-free low-temperature ohmic contact to AlGaN/GaN HEMT. The effects of the annealing method on surface morphology, gate leakage, dynamic on-resistance (RON), and other device characteristics are investigated and presented in this paper. By using a low-temperature annealing atmosphere or selective annealing method, gate-first Si-CMOS compatible AlGaN/GaN HEMT technology can be realized for high frequency and power application.

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“…Thus, it is easier to realize low contact resistance. [2] On the contrary, TiN spikes are not found in the Au-free ohmic contacts. [3] Thus, higher annealing temperature is required to form high quality of Au-free ohmic contacts.…”

Section: Introductionmentioning

confidence: 99%

Protection of isolated and active regions in AlGaN/GaN HEMTs using selective laser annealing*

Hou¹,

Xie²,

Guo³

et al. 2021

Chinese Phys. B

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AlGaN/GaN high-electron-mobility transistors with Au-free ohmic contacts are fabricated by selective laser annealing and conventional rapid thermal annealing. The current transport mechanism of ohmic contacts is investigated. High-temperature annealing can be avoided in the isolated region and the active region by selective laser annealing. The implanted isolation leakage current is maintained 10−6 mA/mm even at 1000 V after selective laser annealing. On the contrary, high-temperature annealing will cause obvious degradation of the isolation. The morphology of AlGaN surface is measured by atomic force microscope. No noticeable change of the AlGaN surface morphology after selective laser annealing, while the root-mean-square roughness value markedly increases after rapid thermal annealing. The smaller frequency dispersion of capacitance–voltage characteristics confirms the lower density of surface states after selective laser annealing. Thus, dynamic on-resistance is effectively suppressed.

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Mechanism of Ti/Al/Ni/Au ohmic contacts to AlGaN/GaN heterostructures via laser annealing

Cited by 4 publications

References 30 publications

Electronic and optical properties of GaN–MoS₂ heterostructure from first-principles calculations*

Electronic and optical properties of GaN–MoS₂ heterostructure from first-principles calculations*

Process of Au-Free Source/Drain Ohmic Contact to AlGaN/GaN HEMT

Protection of isolated and active regions in AlGaN/GaN HEMTs using selective laser annealing*

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Mechanism of Ti/Al/Ni/Au ohmic contacts to AlGaN/GaN heterostructures via laser annealing

Cited by 4 publications

References 30 publications

Electronic and optical properties of GaN–MoS2 heterostructure from first-principles calculations*

Electronic and optical properties of GaN–MoS2 heterostructure from first-principles calculations*

Process of Au-Free Source/Drain Ohmic Contact to AlGaN/GaN HEMT

Protection of isolated and active regions in AlGaN/GaN HEMTs using selective laser annealing*

Contact Info

Product

Resources

About

Electronic and optical properties of GaN–MoS₂ heterostructure from first-principles calculations*

Electronic and optical properties of GaN–MoS₂ heterostructure from first-principles calculations*