GaN‐on‐Si wafers for HEMTs with high power‐driving capability

Hu, Cheng-Yu; Murad, S. K.; Nishikawa, Atsushi; Groh, Lars; Pinos, Andrea; Tan, W. S.; Chitnis, A.; Yagi, Takuma; Lutgen, S.

doi:10.1002/pssc.201300534

Cited by 5 publications

(3 citation statements)

References 2 publications

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“…The investigated MISHEMT devices were fabricated on 150 mm GaN on Si wafers, grown by MOVPE. In detail, the GaN‐based material stack consisted of a 3 nm thick GaN‐cap layer and a 20 nm thick Al 0.23 Ga 0.77 N barrier layer on a 1–2 µm i‐GaN channel layer, a 3–4 µm highly resistive buffer for strain management and an AlN nucleation layer on Si .…”

Section: Methodsmentioning

confidence: 99%

Analysis of threshold voltage instability in AlGaN/GaN MISHEMTs by forward gate voltage stress pulses

Winzer

Schuster

Hentschel

et al. 2016

Physica Status Solidi (a)

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We report on the investigation of the V th drift behaviour of AlGaN/GaN MISHEMTs upon forward gate voltage stress in dependence of stress bias and stress time. The pulsed measurements allow for the evaluation of the operational regime for optimum device efficiency. We compared the effect of two different high-k gate dielectric materials with similar equivalent oxide thickness e 0 e r /t high-k on the V th instability in order to separate the influence of the heterojunction design and the high-k/GaN-cap interface from the bulk high-k. The matched gate capacitance coupling of the studied Al 2 O 3 and HfO 2 gate dielectric results in an nearly identical critical forward gate voltage, where the AlGaN barrier potential is lowered and severe threshold voltage shift (DV th ) into the positive voltage direction is induced. Beyond this critical forward voltage, detailed time-dependent stress pulse measurements from 1 ms to 1000 s revealed an immediate electron injection and trapping at the oxide/GaN interface for stress pulses with t stress ! 1 ms. The presented results of V th drift analysis demonstrate the limits of the maximum tolerable forward gate voltage of the investigated Al 2 O 3 and HfO 2 MISHEMTs, although the excellent low-leakage currents of the insulated gate would imply a potentially higher gateoverdrive.

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Section: Methodsmentioning

confidence: 99%

Analysis of threshold voltage instability in AlGaN/GaN MISHEMTs by forward gate voltage stress pulses

Winzer

Schuster

Hentschel

et al. 2016

Physica Status Solidi (a)

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“…The investigated GaN-based material stack consisted of a 3 nm thick GaN cap layer and a 20 nm thick Al 0.21 Ga 0.79 N barrier layer, grown by MOVPE on a 1-2 lm i-GaN channel (buffer) layer, a 3-4 lm highly resistive buffer for strain management and an AlN nucleation layer on a 150 mm Si substrate. 21,22 First, ohmic contacts (Ti/Al/Ni/Ti/Pt) were evaporated through a shadow mask and alloyed at 850 C in N 2 for 38 s by rapid thermal annealing. Prior to the high-k deposition, samples were sonicated in acetone, isopropanol, and deionized water for 5 min each, followed by a wet-chemical clean with 1:10 HCl:DI-H 2 O for 30 s. Al 2 O 3 and HfO 2 thin films were grown by thermal ALD with each a thickness of 2, 4, 6, 9, 12, 15, 20, and 25 nm as single samples and 45 nm for the terrace etching.…”

Section: Methodsmentioning

confidence: 99%

Detailed analysis of oxide related charges and metal-oxide barriers in terrace etched Al2O3 and HfO2 on AlGaN/GaN heterostructure capacitors

Winzer

Szabó

Ocker

et al. 2015

Journal of Applied Physics

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Articles you may be interested inHigh quality HfO2/p-GaSb (001) metal-oxide-semiconductor capacitors with 0.8 nm equivalent oxide thickness Appl. Phys. Lett. 105, 222103 (2014); 10.1063/1.4903068 Quantitative characterization of interface traps in Al2O3/AlGaN/GaN metal-oxide-semiconductor high-electronmobility transistors by dynamic capacitance dispersion technique Appl. Phys. Lett. 103, 033510 (2013); 10.1063/1.4813912 Study of gate oxide traps in HfO2/AlGaN/GaN metal-oxide-semiconductor high-electron-mobility transistors by use of ac transconductance method A comprehensive analytical model for threshold voltage calculation in GaN based metal-oxide-semiconductor high-electron-mobility transistors Appl. Phys. Lett. 100, 113509 (2012); 10.1063/1.3694768 Trap states in AlGaN/GaN metal-oxide-semiconductor structures with Al 2 O 3 prepared by atomic layer depositionIn this work, we present the terrace etching technique to obtain excessive thickness series of atomic layer deposition (ALD) grown Al 2 O 3 and HfO 2 on GaN-cap/AlGaN/GaN heterostructures allowing for the detailed study of oxide charge distribution and its impact of the metal-insulatorsemiconductor high electron mobility transistor (MISHEMT) threshold voltage. By modeling the experimental plot of threshold voltage versus oxide thickness on the basis of experimentally determined two-dimensional electron gas charge density in AlGaN/GaN MISHEMTs, we separated the interface and bulk charge components and determined the oxide-metal barrier height for the investigated gate dielectrics. In both Al 2 O 3 and HfO 2 gate dielectrics, the oxide charges are mainly located at the oxide/GaN interface. Determining the interface trap charges from comparison of the pulsed capacitance-voltage (CV) technique with very fast voltage sweep to the modulation type CV method with slow DC voltage ramp, we extracted positive fixed charges of N Ox ¼ 2:7 Â 10 12 cm À2 for Al 2 O 3 and N Ox ¼ 7:8 Â 10 12 cm À2 for HfO 2 . We found a strong V th shift of opposite direction for both high-k materials, corresponding to negatively charged up trap states at the HfO 2 /GaN interface and positively charged up trap states at the Al 2 O 3 /GaN interface. The evaluation of the metal-oxide barrier height in dependence of the metal work function followed the trend of the Schottky model, whereas HfO 2 showed less Fermi level pinning compared to Al 2 O 3 indicating the presence of an increased number of interface states in Al 2 O 3 on GaN. V C 2015 AIP Publishing LLC. [http://dx.

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“…Besides, after epitaxy the substrates can easily be dissolved in diluted acids which makes contacting of epitaxial layers from both sides feasible (Liu, 2004;Veličkov et al, 2008). Fascinating new possibilities are offered by the integration of GaN in silicon technologie, especially for High-Electron-Mobility Transistors (HEMTs) (Hu et al, 2014). Even if the lattice mismatch for (0001) GaN on (111) Si is as large as 17%, satisfactory layers can be grown in such "GaN-on-Si" process by metal-organic chemical vapor deposition (MOCVD) using graded buffer layers (Drechsel et al, 2012).…”

Section: Binary Compound Derived From Diamond and Lonsdaleitementioning

confidence: 99%

Electronic materials with a wide band gap: recent developments

Klimm¹

2014

IUCrJ

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The development of semiconductor electronics is reviewed briefly, beginning with the development of germanium devices (band gap E g = 0.66 eV) after World War II. A tendency towards alternative materials with wider band gaps quickly became apparent, starting with silicon (E g = 1.12 eV). This improved the signal-to-noise ratio for classical electronic applications. Both semiconductors have a tetrahedral coordination, and by isoelectronic alternative replacement of Ge or Si with carbon or various anions and cations, other semiconductors with wider E g were obtained. These are transparent to visible light and belong to the group of wide band gap semiconductors. Nowadays, some nitrides, especially GaN and AlN, are the most important materials for optical emission in the ultraviolet and blue regions. Oxide crystals, such as ZnO and -Ga 2 O 3 , offer similarly good electronic properties but still suffer from significant difficulties in obtaining stable and technologically adequate p-type conductivity.

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GaN‐on‐Si wafers for HEMTs with high power‐driving capability

Cited by 5 publications

References 2 publications

Analysis of threshold voltage instability in AlGaN/GaN MISHEMTs by forward gate voltage stress pulses

Analysis of threshold voltage instability in AlGaN/GaN MISHEMTs by forward gate voltage stress pulses

Detailed analysis of oxide related charges and metal-oxide barriers in terrace etched Al2O3 and HfO2 on AlGaN/GaN heterostructure capacitors

Electronic materials with a wide band gap: recent developments

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