Ti/Al/Ti/Ni/Au ohmic contacts on AlGaN/GaN high electron mobility transistors with improved surface morphology and low contact resistance

Chiu, Yu Sheng; Lin, Tai Ming; Nguyễn, Hồng Quân; Weng, Yu Chen; Nguyen, Chi Lang; Lin, Yueh Chin; Yu, Hung Wei; Chang, Edward Yi; Lee, Ching-Ting

doi:10.1116/1.4862165

Cited by 14 publications

(3 citation statements)

References 16 publications

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“…For the reference sample (w/o implantation), ohmic contact was performed by thermal metallization at 850 °C, showing a rough surface after thermal annealing. The rough surface was due to the interdiffusion of ohmic contact metals, which result in bumpy surfaces after high temperature annealing [15,16]. Due to heavily doped S/D regions by ion implantation, non-alloyed ohmic contact with excellent smooth surface morphology was realized.…”

Section: Resultsmentioning

confidence: 99%

Non-thermal alloyed ohmic contact process of GaN-based HEMTs by pulsed laser annealing

Tzou

Hsieh

Chen

et al. 2016

Semicond. Sci. Technol.

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We have demonstrated Si implantation incorporation into GaN HEMTs with a non-alloyed ohmic contact process. We optimized the power density of pulsed laser annealing to activate implanted Si dopants without a thermal metallization process. The experimental results show that the GaN surface will be reformed under the high power density of the illumination conditions. It provides a smooth surface for following contact engineering and leads to comparable contact resistance. The transmission line model (TLM) measurement shows a lower contact resistance to 6.8×10 −7 Ω•cm 2 via non-alloyed contact technology with significantly improved surface morphology of the contact metals. DC measurement of HEMTs shows better current and onresistance. The on-resistance could be decreased from 2.18 to 1.74 mΩ-cm 2 as we produce a lower contact resistance. Pulsed laser annealing also results in lower gate leakage and smaller dispersion under a pulse I-V measurement, which implies that the density of the surface state is improved.

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Section: Resultsmentioning

confidence: 99%

Non-thermal alloyed ohmic contact process of GaN-based HEMTs by pulsed laser annealing

Tzou

Hsieh

Chen

et al. 2016

Semicond. Sci. Technol.

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“…The complex multilayer approach such as Ti/Al/Au, Ti/Au/Ni, and Ti/Al/Ni/Au as commonly used for GaN-based power devices has also been reported for β-Ga 2 O 3 to form ohmic contacts. ,,,− ,− In GaN technology, the role of each layer in such complex metal stacks as Ti/Al/Ni/Au is well understood . For example, in such ohmic metal stacks, the first metal layer, which has good adhesion with the substrate and lower work function, like Ti, is the contact layer.…”

Section: Ohmic Contacts To Ga2o3mentioning

confidence: 99%

A Comprehensive Review on Recent Developments in Ohmic and Schottky Contacts on Ga₂O₃ for Device Applications

Sheoran

Kumar

Singh

2022

ACS Appl. Electron. Mater.

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Ultrawide bandgap β-gallium oxide (β-Ga2O3) is emerging as a viable candidate for next-generation high-power electronics, including Schottky barrier diodes (SBDs) and field-effect transistors (FETs). This is due to its excellent material properties such as ultrawide bandgap of 4.6–4.9 eV, high breakdown electric field of 8 MV/cm, very high Baliga’s figure of merit (BFOM) and mature technology for large bulk single crystals, and epitaxial techniques with controllable n-type doping. Ohmic and rectifying metal–semiconductor contacts on β-Ga2O3 have been developed over the past decade. This work comprehensively reviews the recent development of metal–semiconductor contacts on β-Ga2O3. We start with basic concepts of metal–semiconductor contacts, which is followed by summarizing the current literature on ohmic and Schottky contacts on β-Ga2O3. Finally, the status of high-power Schottky diode contact on β-Ga2O3 is presented.

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“…Various methods have been investigated over time to improve ohmic contacts. Some of the useful methodologies include Ti/Al/Ni/Au, Ti/Al/Ti/Ni/Au, Ti/Al/Mo/Au, and Ti/Al/Ti/Au metal stacks which show low contact resistances . Doping by ion implantation in source and drain regions is also found to be a useful method to reduced contact resistance .…”

Section: Introductionmentioning

confidence: 99%

Reduced Contact Resistance and Improved Transistor Performance by Surface Plasma Treatment on Ohmic Regions in AlGaN/GaN HEMT Heterostructures

Yadav

Upadhyay

Meer

et al. 2017

Physica Status Solidi (a)

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A significantly reduced contact resistance and an improved DC and RF performance is demonstrated for AlGaN/GaN high electron mobility transistors by surface plasma treatments on ohmic regions in GaN‐based heterostructures. Various plasma processes using BCl3, Cl2, Ar, SF6, and their combinations are considered. While it is known that certain plasma treatments can remove native oxide and thereby reduce the ohmic contact resistance, detailed experiments are performed to further enhance the understanding. In addition, a second aspect of the plasma treatment is shown, where the controlled physical component of the etching process can improve the AlGaN surface morphology. This in turn can reduce the tunneling resistance for the carriers from the alloyed contact to the two‐dimensional electron gas. The contact resistance is found to decrease to 0.10 from 0.65 Ω mm for Ar, Cl2, and BCl3 treated sample in comparison to that of the control sample. The corresponding transconductance, saturation drain current, and unity current gain frequency are found to increase by 30, 37, and 41% for the high electron mobility transistors fabricated on the same sample.

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Ti/Al/Ti/Ni/Au ohmic contacts on AlGaN/GaN high electron mobility transistors with improved surface morphology and low contact resistance

Cited by 14 publications

References 16 publications

Non-thermal alloyed ohmic contact process of GaN-based HEMTs by pulsed laser annealing

Non-thermal alloyed ohmic contact process of GaN-based HEMTs by pulsed laser annealing

A Comprehensive Review on Recent Developments in Ohmic and Schottky Contacts on Ga₂O₃ for Device Applications

Reduced Contact Resistance and Improved Transistor Performance by Surface Plasma Treatment on Ohmic Regions in AlGaN/GaN HEMT Heterostructures

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Ti/Al/Ti/Ni/Au ohmic contacts on AlGaN/GaN high electron mobility transistors with improved surface morphology and low contact resistance

Cited by 14 publications

References 16 publications

Non-thermal alloyed ohmic contact process of GaN-based HEMTs by pulsed laser annealing

Non-thermal alloyed ohmic contact process of GaN-based HEMTs by pulsed laser annealing

A Comprehensive Review on Recent Developments in Ohmic and Schottky Contacts on Ga2O3 for Device Applications

Reduced Contact Resistance and Improved Transistor Performance by Surface Plasma Treatment on Ohmic Regions in AlGaN/GaN HEMT Heterostructures

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A Comprehensive Review on Recent Developments in Ohmic and Schottky Contacts on Ga₂O₃ for Device Applications