Nb-Ti/Al/Ni/Au based ohmic contacts to AlGaN/GaN

Vanko, G.; Lalinský, T.; Mozolová, Ž.; Liday, Jozef; Vogrinčič, Peter; Vincze, Á.; Uherek, F.; Hašc̆ı́k, Š.; Kostič, I.

doi:10.1016/j.vacuum.2007.07.020

Cited by 33 publications

(13 citation statements)

References 4 publications

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“…In the C‐HEMT process technology there is no “MESA” isolation etching needed, so the surface leakage currents induced by the traps situated at the plasma‐etched surface of GaN buffer layer should not be considered. In the first step, ohmic contacts of circular source and drain surround are formed using Nb/Ti/Al/Ni/Au metallic system, alloyed at 850 °C for 35 s . Sequential electron beam evaporation of Ir/Al gate multilayers (7 periods of Ir/Al) followed by top Ir layer and lift‐off are carried out subsequently to form 100 nm thick ring (annulus) gate contacts of variable area in the second step.…”

Section: Methodsmentioning

confidence: 99%

Ir/Al multilayer Gates for High Temperature Operated AlGaN/GaN HEMTs

Lalinský

Vanko

Dobročka

et al. 2017

Physica Status Solidi (a)

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The fabrication and characterization of the sequentially evaporated Ir/Al multilayer gates of AlGaN/GaN circular high electron mobility transistors formed by high temperature oxidation is reported. Annealing at temperature of 800 °C, for 60 s in O2 ambient makes possible to form a sharp gate interface with a high Schottky barrier height at RT (φb = 1.2 eV). It is also shown that high temperature oxidation can be an effective approach in reducing of both the gate and drain leakage currents of high electron mobility transistors (more than six orders). A comprehensive microstructural, electrical, and electro‐thermal characterization of the Ir/Al gates is carried out to study the thermal stability of the gate interface and high temperature performance of the devices. Stable operation of the devices with multilayer Ir/Al gates in the temperature range up to 500 °C is demonstrated. Here, it is proposed that the thermal stability of the interface is controlled by the formed aluminum oxide interfacial layer. Finally, perfectly clear pinch‐off characteristics and thermally induced threshold voltage (Vth) instability as low as −0.58 mV °C−1 are achieved.

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Section: Methodsmentioning

confidence: 99%

Ir/Al multilayer Gates for High Temperature Operated AlGaN/GaN HEMTs

Lalinský

Vanko

Dobročka

et al. 2017

Physica Status Solidi (a)

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“…GaN layers were grown by low-pressure metal-organic vapour phase epitaxy on sapphire (Al 2 O 3 ) and silicon-carbide (4H SiC) substrates. Nb/Ti/Al/Ni/Au metallic system was used to form alloyed ohmic contacts to Al x Ga 1-x N/GaN heterostructures [4]. Ni/Au metallic system was used to form the Schottky gate contacts.…”

Section: Methodsmentioning

confidence: 99%

Defects in schottky diodes based on AlGaN/GaN heterostructures

Stuchlíková

Kósa

Benkovska

et al. 2014

The Tenth International Conference on Advanced Semiconductor Devices and Microsystems

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In this paper, the investigation of four types of Schottky-gate structures prepared by low-pressure metal-organic vapour phase epitaxy on sapphire and 4H-SiC substrates, by the deep level transient Fourier spectroscopy is presented. Fifteen deep energy levels have been identified (activation energies: 0.12, 0.26, 0.28, 0.48, 0.50, 0.69, 0.72, 0.75, 0.76, 1.02, 1.23, 1.28, 1.35, 1.57, 1.58 eV). The correlation between deep levels observed on different structure types is discussed. 1.

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“…In the next step source/drain alloyed ohmic contacts based on Nb/Ti/Al metallic system were formed at 850 C for 35 s [8]. After gate windows with 2 pm length were opened by a contact photolithography, a specific surface plasma processing was performed.…”

Section: Methodsmentioning

confidence: 99%

Impact of SF₆ Plasma on DC and Microwave Performance of AIGaN/GaN HEMT Structures

Vanko

Lalinský

Tomáška

et al. 2008

2008 International Conference on Advanced Semiconductor Devices and Microsystems

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and gabriel.vanko(savba.skThe improved dc and microwave properties of 2 pm gate length AlGaN/GaN based HEMT structures were observed after applying of a novel approach in the forming of the Schottky gate interface. The new approach uses a shallow recessgate plasma etching of AlGaN barrier layer in combination with "in-situ" SF6 surface plasma treatment under Schottky gate. A significant improvement in both the current gain cut-offfrequency (f) and maximum oscillation frequency (fnax) were demonstrated. The exact mechanism to explain the improvedperformance of the SF6 plasma treated HEMTs is in progress. A great potential of the approach for sub-micrometer gate length technology ofHEMTs is also emphasized.

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Nb-Ti/Al/Ni/Au based ohmic contacts to AlGaN/GaN

Cited by 33 publications

References 4 publications

Ir/Al multilayer Gates for High Temperature Operated AlGaN/GaN HEMTs

Ir/Al multilayer Gates for High Temperature Operated AlGaN/GaN HEMTs

Defects in schottky diodes based on AlGaN/GaN heterostructures

Impact of SF₆ Plasma on DC and Microwave Performance of AIGaN/GaN HEMT Structures

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Nb-Ti/Al/Ni/Au based ohmic contacts to AlGaN/GaN

Cited by 33 publications

References 4 publications

Ir/Al multilayer Gates for High Temperature Operated AlGaN/GaN HEMTs

Ir/Al multilayer Gates for High Temperature Operated AlGaN/GaN HEMTs

Defects in schottky diodes based on AlGaN/GaN heterostructures

Impact of SF6 Plasma on DC and Microwave Performance of AIGaN/GaN HEMT Structures

Contact Info

Product

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Impact of SF₆ Plasma on DC and Microwave Performance of AIGaN/GaN HEMT Structures