Regrown Vertical GaN p–n Diodes with Low Reverse Leakage Current

Pickrell, Gregory; Armstrong, Andrew M.; Allerman, Andrew A.; Crawford, Mary H.; Cross, Karen Charlene; Glaser, Caleb; Abate, Vincent M.

doi:10.1007/s11664-019-07098-6

Cited by 12 publications

(8 citation statements)

References 17 publications

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“…However, they did the regrowth on a non-etched surface whereas dry etching is almost inevitable in selective regrowth. Recently, Pickrell et al found that regrown diodes including dry etching process prior to the p-GaN regrowth showed a large Si spike at the regrowth interface and demonstrated significantly higher reverse leakage current than the as-grown diodes [23]. However, they only showed simple current-voltage curves for the etchthen-regrow diodes.…”

Section: Introductionmentioning

confidence: 99%

Reverse Leakage Analysis for As-Grown and Regrown Vertical GaN-on-GaN Schottky Barrier Diodes

Zhou

Deng

et al. 2020

IEEE J. Electron Devices Soc.

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Vertical GaN-on-GaN Schottky barrier diodes based on as-grown and regrown samples were fabricated to investigate the effects of the etch-then-regrow process on device performance. The surface roughness increased slightly after dry etching and decreased after regrowth. According to X-ray diffraction results, the etch-then-regrow process caused a slight increase of defect density due to increased edge dislocations. Schottky parameters extracted from forward current-voltage curves, such as turn-on voltages of 0.74 V and 0.72 V, ideality factors of 1.07 and 1.10, and barrier heights of 1.07 eV and 1.05 eV, were obtained for diodes based on the regrown and as-grown samples, respectively. The breakdown voltage of the regrown sample was much lower than the as-grown sample. The regrowth interface can be regarded as a n-doping GaN layer due to the high interface charge density after the etch-then-regrown process. This equivalent n-doping GaN layer reduced the effective thickness of the UID-GaN under the Schottky contact thus causing lower breakdown voltage for the regrown sample. Poole-Frenkel emission and trap-assisted tunneling processes were responsible for the leakage of both as-grown and regrown samples according to the temperature dependence of the reverse currents.INDEX TERMS Schottky barrier diodes, GaN-on-GaN, regrow, leakage, interface.

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Section: Introductionmentioning

confidence: 99%

Reverse Leakage Analysis for As-Grown and Regrown Vertical GaN-on-GaN Schottky Barrier Diodes

Zhou

Deng

et al. 2020

IEEE J. Electron Devices Soc.

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“…Si enriched GaN interfaces are a commonly observed feature of regrowth. [ 26,27 ] The acidic treatment of Mg‐doped layers with diluted hydrofluoric acid (HF) or BHF, was shown to be an effective removal of the Mg‐rich surface, reducing segregation effects. [ 28 ] In our case, a positive impact was also noticed, which is consistent with the aforementioned electrical characteristics, as the Mg concentration seemed to drop earlier after the RI.…”

Section: Algan/gan Overgrowthmentioning

confidence: 99%

Growth and Fabrication of Quasivertical Current Aperture Vertical Electron Transistor Structures

Doering

Driad

Mueller

et al. 2020

Physica Status Solidi (a)

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The current aperture vertical electron transistor (CAVET) combines the high carrier mobility of the AlGaN/GaN heterostructure with the better electric field distribution of the vertical topology, allowing for higher power densities if compared with lateral high electron mobility transistors (HEMTs). The formation of a current blocking layer (CBL), without degenerating the aperture region and the subsequently overgrown AlGaN/GaN heterostructure is the key building block of such devices. Herein, a comparison of GaN:Mg nonplanar selective area growth (SAG) and Mg‐ion implantation is carried out primarily focusing on structural evolution, Mg distribution, and 2D electron gas (2DEG) performance. The epitaxial growth process in SAG is correlated to local growth increase and ridge development, and then optimized regarding mesa filling. AlGaN/GaN regrowth is analyzed regarding structural evolution after overgrowth and Mg distribution into the GaN channel. Considerably lower Mg‐distribution into subsequently grown layers is detected for implanted samples in agreement with the electrical performance of the overgrown AlGaN/GaN heterostructures. A GaN‐on‐Si quasivertical CAVET structure with an Mg‐implanted CBL and 250 nm channel thickness is fabricated. High surface quality and proper 2DEG performance demonstrate the potential use of GaN‐on‐Si CAVET's using Mg implantation for CBL fabrication.

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“…Such a spike has also been observed in samples where there is no Si doping as well as ones where there was simply a pause in epitaxy, with no change in the reactor, to allow changes in growth parameters such as temperature and pressure. SIMS profiles from Pickrell et al (2019) reveal significantly greater Si concentration in GaN due to air contamination when compared with growth interruptions with temperature ramps. In both cases, the oxygen trace remained at the detection limit.…”

Section: Introductionmentioning

confidence: 99%

“…Some limitations of the WDX technique are that depth resolution is a function of the electron accelerating voltage, which must be high enough to excite all the relevant X-ray lines, preferably with an overvoltage ratio of at least 2 to ensure accurate analysis, particularly when approaching detection limits. These limitations also introduce constraints on the minimum sample thickness (Newbury, 2002) and depth profiling, where SIMS performs strongly including for nitride semiconductor structures (Martin et al, 2006; Wei et al, 2014; Michałowski et al, 2019; Pickrell et al, 2019). Two of these works employed time-of-flight SIMS (TOF-SIMS) which has a number of advantages over D-SIMS, including dual-source depth profiling where the two ion beams have been optimized for their respective tasks, although work is needed to achieve the same detection limit for dopants (Klump et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

“…In this paper, we will consider how to measure Si, at dopant levels, in semiconductor epilayers such as GaN and Al x Ga 1– x N where inherent contamination of the sample surfaces with additional Si is suspected to be the cause of a discrepancy between the results from D-SIMS and WDX. Si incorporation is known to be a contaminant during the metal-organic chemical vapor deposition (MOCVD) growth of GaN and Al x Ga 1– x N (Koleske et al, 2002; Pickrell et al, 2019). Typical growth temperatures are in the region of 1,100°C, in order to promote the breakup of the ammonia molecules and adatom mobility on the growing surface, and it should be noted that the graphite susceptors used to heat and support the substrate wafer during growth are often coated with SiC to provide robustness.…”

Section: Introductionmentioning

confidence: 99%

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Quantification of Trace-Level Silicon Doping in Al_xGa_1–xN Films Using Wavelength-Dispersive X-Ray Microanalysis

et al. 2021

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Wavelength-dispersive X-ray (WDX) spectroscopy was used to measure silicon atom concentrations in the range 35–100 ppm [corresponding to (3–9) × 1018 cm−3] in doped Al x Ga1–xN films using an electron probe microanalyser also equipped with a cathodoluminescence (CL) spectrometer. Doping with Si is the usual way to produce the n-type conducting layers that are critical in GaN- and Al x Ga1–xN-based devices such as LEDs and laser diodes. Previously, we have shown excellent agreement for Mg dopant concentrations in p-GaN measured by WDX with values from the more widely used technique of secondary ion mass spectrometry (SIMS). However, a discrepancy between these methods has been reported when quantifying the n-type dopant, silicon. We identify the cause of discrepancy as inherent sample contamination and propose a way to correct this using a calibration relation. This new approach, using a method combining data derived from SIMS measurements on both GaN and Al x Ga1–xN samples, provides the means to measure the Si content in these samples with account taken of variations in the ZAF corrections. This method presents a cost-effective and time-saving way to measure the Si doping and can also benefit from simultaneously measuring other signals, such as CL and electron channeling contrast imaging.

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Regrown Vertical GaN p–n Diodes with Low Reverse Leakage Current

Cited by 12 publications

References 17 publications

Reverse Leakage Analysis for As-Grown and Regrown Vertical GaN-on-GaN Schottky Barrier Diodes

Reverse Leakage Analysis for As-Grown and Regrown Vertical GaN-on-GaN Schottky Barrier Diodes

Growth and Fabrication of Quasivertical Current Aperture Vertical Electron Transistor Structures

Quantification of Trace-Level Silicon Doping in Al_xGa_1–xN Films Using Wavelength-Dispersive X-Ray Microanalysis

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Regrown Vertical GaN p–n Diodes with Low Reverse Leakage Current

Cited by 12 publications

References 17 publications

Reverse Leakage Analysis for As-Grown and Regrown Vertical GaN-on-GaN Schottky Barrier Diodes

Reverse Leakage Analysis for As-Grown and Regrown Vertical GaN-on-GaN Schottky Barrier Diodes

Growth and Fabrication of Quasivertical Current Aperture Vertical Electron Transistor Structures

Quantification of Trace-Level Silicon Doping in AlxGa1–xN Films Using Wavelength-Dispersive X-Ray Microanalysis

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Product

Resources

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Quantification of Trace-Level Silicon Doping in Al_xGa_1–xN Films Using Wavelength-Dispersive X-Ray Microanalysis