Formation of Ohmic contacts in AlGaN/GaN HEMT structures at 500°C by Ohmic contact recess etching

Lau, W. S.; Tan, Joy B. H.; Singh, Bhupinder

doi:10.1016/j.microrel.2009.02.010

Cited by 26 publications

(15 citation statements)

References 14 publications

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“…High Electron Mobility Transistors (HEMTs) 1 have been the subject of research of continuous expansion for some years. This kind of transistors is used in III-nitride power devices, where a 2D electron gas is formed at the interface between the AlGaN channel and the GaN substrate.…”

Section: Introductionmentioning

confidence: 99%

Quantitative determination of elemental diffusion from deeply buried layers by photoelectron spectroscopy

Zborowski

Renault

Torres

et al. 2018

Journal of Applied Physics

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The recent advances in the inelastic background analysis of XPS spectra recorded with hard X-rays (HAXPES) make this method a powerful, non-destructive solution to retrieve the depth distribution of deeply buried elements. In this work, we apply this technique to study diffusion phenomena, upon annealing, in power transistor devices. We present a complete analysis of a sample under different stages of the fabrication process. We investigate the accuracy of the determination of the elemental depth distributions and concentrations with the inelastic background analysis. This is done by cross-checking with destructive techniques such as TEM/EDX and XPS depth profiling, and we shed light on the complementarities with HAXPES core-level analysis. We obtain consistent results which show the formation of an inhomogeneous structure, consisting of a blend of Al, Ga, and Ta, created during annealing. The inelastic background analysis permits us to successfully retrieve the depth distributions of Al, Ga, and Ta as well as the concentration of these elements in each layer, over 70 nm below the surface. This is a reliable solution to investigate diffusion phenomena and improve the fabrication processes of devices with critical and deeply buried interfaces.

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Section: Introductionmentioning

confidence: 99%

Quantitative determination of elemental diffusion from deeply buried layers by photoelectron spectroscopy

Zborowski

Renault

Torres

et al. 2018

Journal of Applied Physics

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“…The formation of low resistance ohmic contacts to HEMTs is a key issue in the fabrication process of AlGaN/GaN HEMTs. These ohmic contacts are required to produce a smooth surface morphology and well-defined edge acuity [15]. Pre-metal-deposition ion etching is also a widely used technique for improving metal to semiconductor contact resistivity in HEMT [16].…”

Section: Introductionmentioning

confidence: 99%

Optimization of Ohmic Contact Metallization Process for AlGaN/GaN High Electron Mobility Transistor

Cho¹,

Kim²

2013

Transactions on Electrical and Electronic Materials

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In this paper, a manufacturing process was developed for fabricating high-quality AlGaN/GaN high electron mobility transistors (HEMTs) on silicon carbide (SiC) substrates. Various conditions and processing methods regarding the ohmic contact and pre-metal-deposition BCl 3 etching processes were evaluated in terms of the device performance. In order to obtain a good ohmic contact performance, we tested a Ti/Al/Ta/Au ohmic contact metallization scheme under different rapid thermal annealing (RTA) temperature and time. A BCl 3 -based reactive-ion etching (RIE) method was performed before the ohmic metallization, since this approach was shown to produce a better ohmic contact compared to the as-fabricated HEMTs. A HEMT with a 0.5 μm gate length was fabricated using this novel manufacturing process, which exhibits a maximum drain current density of 720 mA/mm and a peak transconductance of 235 mS/mm. The X-band output power density was 6.4 W/mm with a 53% power added efficiency (PAE).

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“…AlGaN/GaN HEMT comprises of AlGaN/GaN heterostructure on a substrate layer, with typically Ti/Al based source and drain [35] and Ni gate metal [17]. Device schematic is presented in Fig.…”

Section: Device Schematic and Principle Of Operationsmentioning

confidence: 99%

“…It was experimentally shown by Kowalczyk et al that titanium reduces the Ga 2 O 3 oxide [52]. There are also many procedures of chemical pretreatment to remove the oxide layer, such as HCl [53], aqua regia [48] or HF:HCl:H 2 O [35]. Major problem of the Ti-only and also Ti/Al contacts (i.e.…”

Section: Titaniummentioning

confidence: 99%

“…Ohmic contacts to AlGaN/GaN devices are not yet optimized and attempts are being taken to improve them for example by partially removing the top layers of the heterostructure and forming so-called recessed contact [35,60,107]. The approach to improve Ohmic contacts is focused on two aspects: lowering the contact resistance and decreasing the thermal budget.…”

Section: Introductionmentioning

confidence: 99%

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Gold free contacts to AlGaN/GaN heterostructures

Hajlasz¹

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Formation of Ohmic contacts in AlGaN/GaN HEMT structures at 500°C by Ohmic contact recess etching

Cited by 26 publications

References 14 publications

Quantitative determination of elemental diffusion from deeply buried layers by photoelectron spectroscopy

Quantitative determination of elemental diffusion from deeply buried layers by photoelectron spectroscopy

Optimization of Ohmic Contact Metallization Process for AlGaN/GaN High Electron Mobility Transistor

Gold free contacts to AlGaN/GaN heterostructures

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