Effect of annealing temperature on Ti/Al/Ni/Au ohmic contacts on undoped AlN films

Li, Xuewei; Zhang, Jicai; Sun, Miao; Ye, Binbin; Huang, Jun; Xu, Zhenyi; Dong, Wenxiu; Wang, Jianfeng; Xu, Ke

doi:10.1088/1674-4926/38/11/116002

Cited by 6 publications

(6 citation statements)

References 22 publications

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“…Furthermore, the optimal annealing temperature is determined to be 950 °C since it yields the highest current. Previous reports have confirmed that an AlN ohmic contact is established through the formation of Al–Au, Au–Ti, and Al–Ni alloys . Moreover, the performance of AlN ohmic contacts is assessed by the circular transmission line (CTLM) model .…”

Section: Results and Discussionmentioning

confidence: 90%

“…As depicted in Figure 3d, fitting the total resistance versus ln(R/r) curve using least-squares linear regression yields a specific contact resistance of 0.792 Ω•cm 2 , which is comparable to the reported value for ohmic contacts on the UID polar (0002) AlN film. 26 Building upon the good crystal quality and ohmic contacts, we manufactured lateral SBDs on the semipolar (11− 22) AlN film. In the schematic representation of the lateral AlN SBDs (Figure 4a), the donut-shaped double circle SBDs feature an ohmic contact with a radius of 100 μm, a circular Schottky contact with a diameter of 160 μm, and a 200 μm separation between the two contacts.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…The current versus voltage ( I – V ) curves of the CTLM contacts annealed at 950 °C for 30 s are shown in Figure c, enabling the calculation of specific contact resistivity. As depicted in Figure d, fitting the total resistance versus ln( R / r ) curve using least-squares linear regression yields a specific contact resistance of 0.792 Ω·cm 2 , which is comparable to the reported value for ohmic contacts on the UID polar (0002) AlN film . Building upon the good crystal quality and ohmic contacts, we manufactured lateral SBDs on the semipolar (11–22) AlN film.…”

Section: Results and Discussionmentioning

confidence: 99%

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Semipolar (11–22) AlN Films Grown by Hydride Vapor Phase Epitaxy for Schottky Barrier Diodes

Ji,

Liu,

et al. 2024

Crystal Growth & Design

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High-quality semipolar (11−22) AlN films with a thickness of 8.4 μm are grown on m-plane sapphire by high-temperature hydride vapor phase epitaxy (HVPE). The full widths at half-maximum (FWHMs) of X-ray rocking curves (XRCs) for such films are as small as 641″ and 346″ along [11−23] AlN and [1−100] AlN , respectively. Ohmic contacts with a specific contact resistance of 0.792 Ω•cm 2 are achieved on the unintentionally doped (11−22) AlN films by depositing a Ti/Al/Ni/ Au metal stack, combined with high-temperature rapid annealing at 950 °C. Based on the good crystal quality and ohmic contacts, lateral Schottky barrier diodes (SBDs) are fabricated on the semipolar AlN film. The Ni/Au-AlN SBDs exhibit an ideality factor n of 6.5 and an effective Schottky barrier height (SBH) of 1.12 eV at room temperature. At high temperatures, the ideality factor n falls, while the effective SBH grows, indicating lateral nonuniformities at the metal/semiconductor contact, which can be adequately explained by an inhomogeneous model. Moreover, the large band gap of AlN enables the manufactured SBDs to operate reliably even at a temperature of 450 K.

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Section: Results and Discussionmentioning

confidence: 90%

Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Results and Discussionmentioning

confidence: 99%

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Semipolar (11–22) AlN Films Grown by Hydride Vapor Phase Epitaxy for Schottky Barrier Diodes

Ji,

Liu,

et al. 2024

Crystal Growth & Design

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“…Separate experiments were run with Ti/Al and Ni/Ag, finding no emission in the case of Ti/Al and weaker emission in the case of Ni/Ag. Annealing introduced roughness to the metal layer due to the diffusion of Al, with the common formation of Ni-Al clusters [24][25].…”

Section: Device Fabricationmentioning

confidence: 99%

450 nm Gallium Nitride Alternating Current Light-Emitting Diode

et al. 2020

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Gallium Nitride (GaN) based light-emitting diodes (LEDs) are being utilized in an ever expanding number of applications. The persistent issues, however, have been the use of alternating current (AC) to direct current (DC) converters and the inefficient p-type doping compared to n-type doping. Here, a novel hybrid AC InGaN quantum well (QW) LED without a p-GaN layer is demonstrated at 450 nm. A tunneling LED is fabricated through use of InGaN QWs, combined with a thin Al2O3 dielectric with NiO as the source of the holes. This hybrid InGaN LED utilizes Fowler-Nordheim tunneling and band bending in order to inject holes into the active region. Due to the symmetric nature of the tunneling, hole or electron injection through the top oxide layer leads to AC performance. Room temperature and cryogenic I-V measurements are performed to evaluate the tunneling mechanism. Tunneling of holes is found to lead to earlier device turn-on of ~0.5 V compared with conventional blue LEDs at ~2 V. The presented work can lead to a number of novel applications such as on-chip communication, monolithic integration with transistors, and LiFi.

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“…Sachenko et al prepared Pd/Ti/Pd/Au on n-type AlN with annealing at 900 °C for 30 s with the specific contact resistivity as low as 0.32 Ω • cm 2 [26]. Recently, Li et al got the Ohmic contacts of 0.379 Ω • cm 2 with Ti/Al/Ni/Au on undoped AlN after annealing at 950 °C [27]. In this work, the effect of surface treatment by oxygen plasma on the Ohmic contacts with Pd/Al/Au on undoped AlN films was studied.…”

Section: Introductionmentioning

confidence: 99%

Effect of oxygen plasma modification on Pd/Al/Au Ohmic contacts on undoped AlN

Li¹,

Xu²,

Lu³

et al. 2019

J. Phys. D: Appl. Phys.

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The influence of surface modification of undoped AlN by oxygen plasma on the Pd/Al/ Au Ohmic contacts was studied. Pd/Al/Au alloys were deposited on undoped AlN films by electron beam evaporation and annealed from 750 °C to 900 °C for 30 s to form metalsemiconductor contacts. All the samples without oxygen plasma treatment were Schottky contacts. After oxygen plasma treatment, the contacts below annealing temperature of 850 °C were Schottky type. However, the contacts changed to be Ohmic type with specific contact resistivity of 3.01 Ω • cm 2 when the annealing temperature was 900 °C. The samples were characterized by scanning electron microscopy and x-ray diffraction, which indicated that the formation of AlPd alloy was believed to play a key role for the formation of low Ohmic contacts. The first-principle calculation indicated that the surface modification by oxygen plasma could increase the work function of AlN and therefore benefit the formation of Ohmic contacts. This result can promote the application prospects of AlN in deep ultraviolet optoelectronic devices and high frequency and high power RF devices.

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Effect of annealing temperature on Ti/Al/Ni/Au ohmic contacts on undoped AlN films

Cited by 6 publications

References 22 publications

Semipolar (11–22) AlN Films Grown by Hydride Vapor Phase Epitaxy for Schottky Barrier Diodes

Semipolar (11–22) AlN Films Grown by Hydride Vapor Phase Epitaxy for Schottky Barrier Diodes

450 nm Gallium Nitride Alternating Current Light-Emitting Diode

Effect of oxygen plasma modification on Pd/Al/Au Ohmic contacts on undoped AlN

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