Novel Oxide-Passivated AlGaN/GaN HEMT by Using Hydrogen Peroxide Treatment

Liu, Han-Yin; Chou, Bo-Yi; Hsu, Wei-Chou; Lee, Ching-Sung; Ho, Chiu-Sheng

doi:10.1109/ted.2011.2167512

Cited by 36 publications

(27 citation statements)

References 16 publications

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“…Although no statistical quantities can be derived, the sensitivity of GaP to hydrogen peroxide is evident for post-soaked etched samples. Hydrogen peroxide has shown the ability to form smooth microstructures on AlGaN [47,48] and ZnO [5] surfaces by forming secondary oxide structures, which seems to be the case for pre-soaked etched GaN samples. By soaking them, the change for GaN is diminished, whereas it becomes more evident for GaP.…”

Section: Topography and Hydrophobicitymentioning

confidence: 93%

“…(H 2 O 2 ) provides a greater control of the surface terminal groups, specifically hydroxyl groups from H 2 O 2 degradation. [47,48] This has already been shown to provide better control over surface termination [49] and subsequent surface coverage. [50] As etching techniques require the formation and subsequent dissolution of oxides, the degree of environmental degradation within an aqueous environment should provide insight into the more reactive species on the surface.…”

Section: Introductionmentioning

confidence: 99%

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Comparison of the Stability of Functionalized GaN and GaP

et al. 2015

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Surface functionalization via 1 H,1 H,2 H,2H-perfluoro octanephosphonic acid was done in the presence of phosphoric acid to provide a simplified surface passivation technique for gallium nitride (GaN) and gallium phosphide (GaP). In an effort to identify the leading causes of surface instabilities, hydrogen peroxide was utilized as an additional chemical modification to cap unsatisfied bonds. The stability of the surfaces was studied in an aqueous environment and subsequently characterized. A physical characterization was carried out to evaluate the surface roughness and water hydrophobicity pre and post stability testing via atomic force microscopy and water goniometry. Surface-chemistry changes and solution leaching were quantified by X-ray photoelectron spectroscopy and inductively coupled plasma mass spectrometry. The results indicate a sensitivity to hydroxyl terminated species for both GaN and GaP under aqueous environments, as the increase of the degree of leaching was more significant for hydrogen peroxide treated samples. The results support the notion that hydroxyl species act as precursors to gallium oxide formation and lead to subsequent instability in aqueous solutions.

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Section: Topography and Hydrophobicitymentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Comparison of the Stability of Functionalized GaN and GaP

et al. 2015

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“…Post-growth passivation techniques have become the most popular method to address the deleterious effects of surface state traps and include conformal oxide and nitride depositions [3], [4], [5], [6]. Surface chemical treatments have been investigated to minimize the effects of virtual gating on frequency performance [7], [8], [9]. Alternative approaches for epitaxial passivation have also been given some attention [10].…”

mentioning

confidence: 99%

Suppression of surface-originated gate lag by a dual-channel AlN/GaN high electron mobility transistor architecture

Deen

Storm

Katzer

et al. 2016

Applied Physics Letters

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A dual-channel AlN/GaN high electron mobility transistor (HEMT) architecture is demonstrated that leverages ultra-thin epitaxial layers to suppress surface-related gate lag. Two high-density two-dimensional electron gas (2DEG) channels are utilized in an AlN/GaN/AlN/GaN heterostructure wherein the top 2DEG serves as a quasi-equipotential that screens potential fluctuations resulting from distributed surface and interface states. The bottom channel serves as the transistor's modulated channel. Dual-channel AlN/GaN heterostructures were grown by molecular beam epitaxy on free-standing hydride vapor phase epitaxy GaN substrates. HEMTs fabricated with 300 nm long recessed gates demonstrated a gate lag ratio (GLR) of 0.88 with no degradation in drain current after bias stressed in subthreshold. These structures additionally achieved small signal metrics ft/fmax of 27/46 GHz. These performance results are contrasted with the non-recessed gate dual-channel HEMT with a GLR of 0.74 and 82 mA/mm current collapse with ft/fmax of 48/60 GHz.

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“…Chemical treatments of post-processed devices were carried out by exposure to H 2 O 2 (30% concentrated) or H 2 SO 4 (98% concentrated) solutions for $48 h at room temperature (we did not do a systematic study of the effect of treatment time and temperature but the large treatment time compared to that used in Ref. 10 was thought to be due to the relative stability of the oxides of the GaN cap used in this work). The H 2 SO 4 treatment was also performed pre-gate metal deposition.…”

Section: Resultsmentioning

confidence: 99%

“…In the past, hydrogen peroxide (H 2 O 2 ) treatment on the AlGaN surface was shown 10 to reduce the gate leakage current, but no detailed studies on surface leakage mechanisms were conducted.…”

Section: Introductionmentioning

confidence: 99%

Sulfuric acid and hydrogen peroxide surface passivation effects on AlGaN/GaN high electron mobility transistors

Zaidi

Lee

Guiney

et al. 2014

Journal of Applied Physics

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In this work, we have compared SiNx passivation, hydrogen peroxide, and sulfuric acid treatment on AlGaN/GaN HEMTs surface after full device fabrication on Si substrate. Both the chemical treatments resulted in the suppression of device pinch-off gate leakage current below 1 μA/mm, which is much lower than that for SiNx passivation. The greatest suppression over the range of devices is observed with the sulfuric acid treatment. The device on/off current ratio is improved (from 104–105 to 107) and a reduction in the device sub-threshold (S.S.) slope (from ∼215 to 90 mV/decade) is achieved. The sulfuric acid is believed to work by oxidizing the surface which has a strong passivating effect on the gate leakage current. The interface trap charge density (Dit) is reduced (from 4.86 to 0.90 × 1012 cm−2 eV−1), calculated from the change in the device S.S. The gate surface leakage current mechanism is explained by combined Mott hopping conduction and Poole Frenkel models for both untreated and sulfuric acid treated devices. Combining the sulfuric acid treatment underneath the gate with the SiNx passivation after full device fabrication results in the reduction of Dit and improves the surface related current collapse.

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Novel Oxide-Passivated AlGaN/GaN HEMT by Using Hydrogen Peroxide Treatment

Cited by 36 publications

References 16 publications

Comparison of the Stability of Functionalized GaN and GaP

Comparison of the Stability of Functionalized GaN and GaP

Suppression of surface-originated gate lag by a dual-channel AlN/GaN high electron mobility transistor architecture

Sulfuric acid and hydrogen peroxide surface passivation effects on AlGaN/GaN high electron mobility transistors

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