High resolution physical analysis of ohmic contact formation at GaN-HEMT devices

Graff, Andreas; Simon-Najasek, Michél; Altmann, Frank; Kuzmı́k, J.; Gregušová, D.; Hašc̆ı́k, Š.; Jung, Helmut; Baur, Tobias; Grünenpütt, Jan; Blanck, H.

doi:10.1016/j.microrel.2017.06.031

Cited by 8 publications

(6 citation statements)

References 10 publications

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“…They achieved a sufficiently low contact resistance of 0.7 Ω•mm at a reduced anneal temperature of 600 • C. The contact surfaces of AlGaN were directly treated by the SiCl 4 plasma for 15 s in RIE with self-induced bias of about 300 V. They suggested that the SiCl 4 plasma treatment of AlGaN surface would help to enhance the generation of N vacancies, which may be responsible for the high carrier concentration at the AlGaN surface to form a low contact resistance. The work from Graff et al [75] exhibited consistent results of low contact resistance with the pre-treatment of SiCl 4 .…”

Section: Ohmic Contacts For Source and Drainmentioning

confidence: 71%

“…In the Ti/Al/Ni/Au metal stack, thickness of each metal layer needs to be optimized to achieve low contact resistance and smooth surface. Ti/Al thickness ratio in the metal stack is one of the key factors for the formation of low contact resistance [75]. Research showed that for a given Ni/Au thickness ratio, the lowest contact resistance is obtained at Ti/Al ratio of 1/6 when annealing at 900 • C in N 2 ambient [76].…”

Section: Ohmic Contacts For Source and Drainmentioning

confidence: 99%

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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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Section: Ohmic Contacts For Source and Drainmentioning

confidence: 71%

Section: Ohmic Contacts For Source and Drainmentioning

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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“…SimonNajase et al pro posed a technique for TEM sample preparation of HEMT based on FIB-SEM. [30,[85][86][87] It uses an innovative clamp in situ lifting method combined with the X2 window thinning tech nique, [87][88][89][90] which can significantly improve the quality of the HEMT TEM samples.…”

Section: Power Device-hemtmentioning

confidence: 99%

The Trends of In Situ Focused Ion Beam Technology: Toward Preparing Transmission Electron Microscopy Lamella and Devices at the Atomic Scale

Zhang

Wang

Dong

et al. 2022

Adv Elect Materials

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The increased complexity and scaling down of electronic devices lead to great challenges in extracting an interesting nanoscale area of the device for transmission electron microscopy (TEM) characterization. The traditional TEM sample preparation methods, such as electrolytic polishing, can not precisely process a specific area of the device. Focused ion beam (FIB) technology is an advanced in situ specimen preparation method for TEM. FIB can not only locate specific position and mill a TEM sample with the nanoscale resolution, but also manipulate the sample in a controlled manner in real time. With the development of electronic devices, variations, and optimizations of the FIB method for advanced devices with new structures have been reported. In this review, the TEM sample preparation methods for fin field‐effect transistor, high electron mobility transistor, enhanced dynamic random‐access memory, and 2D material‐based devices are discussed. Their advantages, disadvantages, and an overview of the applications are summarized. Based on current research, future research directions for enhancing the quality of TEM samples are suggested.

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“…The inference is that the depth of these leakage paths extends ∼1.6 μm down from the contact metal, stopping in the superlattice. Transmission electron microscopy (TEM) studies of other Ti/Al based contacts indicate only 5-30 nm of metal diffusion [21], [22] and < 100 nm of contact spiking [23], much less than 1.6 μm. TEM images of this particular contacting process showed no diffusion or spikes [17], which indicates a different cause.…”

Section: Modelmentioning

confidence: 99%

The Impact of Ti/Al Contacts on AlGaN/GaN HEMT Vertical Leakage and Breakdown

Rackauskas

Uren

Stoffels

et al. 2018

IEEE Electron Device Lett.

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Enhanced leakage paths below Ti-/Al-based contacts to GaN-on-Si HEMTs have been identified and studied. Through a novel use of the quasi-static capacitancevoltage technique, the depth of these preferential leakage paths was determined to be ∼1.6 µm, extending down into the superlattice strain relief layer. Along these paths, the material resistivity was reduced by more than a factor of 100 compared to the uncontacted epitaxy. It is suggested that the cause of the additional leakage is decoration of dislocations. This result is important for understanding buffer transport, a critical parameter for breakdown, and buffer charge storage.

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High resolution physical analysis of ohmic contact formation at GaN-HEMT devices

Cited by 8 publications

References 10 publications

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

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

The Trends of In Situ Focused Ion Beam Technology: Toward Preparing Transmission Electron Microscopy Lamella and Devices at the Atomic Scale

The Impact of Ti/Al Contacts on AlGaN/GaN HEMT Vertical Leakage and Breakdown

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