X-ray photoelectron spectroscopy study of (NH4)2Sx-treated Mg-doped GaN layers

Lin, Yow Jon; Tsai, Chang Da; Lyu, Yen Tang; Lee, Ching-Ting

doi:10.1063/1.127086

Cited by 53 publications

(41 citation statements)

References 10 publications

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“…The XPS measure procedures were reported previously. 17,21 The Ga2p core level XPS spectra for the as-cleaned and 20 min (NH 4 ) 2 S x -treated GaN surfaces are shown in Fig. 2a and b, respectively.…”

Section: Methodsmentioning

confidence: 99%

“…14 Prior to the deposition of the metals, the residual native oxide and contamination could be removed from the GaN surface by using several chemi- ( Low Resistive Ohmic Contact Formation on Surface Treated-n-GaN Alloyed at Low Temperature cal solutions, such as KOH, H 3 PO 4 , HCl, HF, and aqua regia etc., 15,16 or an (NH 4 ) 2 S x solution. 17,18 The S would bond with the Ga and occupy the nitrogen-related vacancies. A GaN surface treated with (NH 4 ) 2 S x solution would be protected from oxidation.…”

Section: Introductionmentioning

confidence: 99%

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Low resistive ohmic contact formation on surface treated-n-GaN alloyed at low temperature

Lin

Lee

Hwang

et al. 2001

Journal of Elec Materi

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Ohmic contacts to n-type GaN with low contact resistance were developed by (NH 4 ) 2 S x and KOH+(NH 4 ) 2 S x surface treatments prior to Ti/Al metal deposition. The lowest specific contact resistance of 3.0 × 10 -6 Ω-cm 2 was obtained for Ti/Al contacts in an (NH 4 ) 2 S x -treated GaN layer alloyed at 300°C for 3 min. To obtain the lowest specific contact resistance for a low temperature alloy, the (NH 4 ) 2 S x treatment conditions for both (NH 4 ) 2 S x and KOH+(NH 4 ) 2 S x -treated n-GaN layers have been investigated and the mechanism for ohmic formation in low temperature alloys analyzed.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Low resistive ohmic contact formation on surface treated-n-GaN alloyed at low temperature

Lin

Lee

Hwang

et al. 2001

Journal of Elec Materi

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“…62 Fitting parameters are summarized in Table 2. N-Ga peak positions are similar to data acquired using monochromatic Al Ka (Fig.…”

Section: 62mentioning

confidence: 99%

“…Energy position and FWHM values for GaN template are close to earlier reported values. 58,59,62 Fitting parameters are summarized in Table 2. Similar to Ga 3d spectra, FWHM of N-Ga increases for LMBE grown samples and it is highest for nanowall network grown at 30 Hz.…”

Section: Electronic Structures Of Gan Lm and Nanowalls Networkmentioning

confidence: 99%

Structural, optical and electronic properties of homoepitaxial GaN nanowalls grown on GaN template by laser molecular beam epitaxy

et al. 2015

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aWe have grown homoepitaxial GaN nanowall networks on GaN template using an ultra-high vacuum laser assisted molecular beam epitaxy system by ablating solid GaN target under a constant r.f. nitrogen plasma ambient. The effect of laser repetition rate in the range of 10 to 30 Hz on the structural properties of the GaN nanostructures has been studied using high resolution X-ray diffraction, field emission scanning electron microscopy and Raman spectroscopy. The variation of the laser repetition rate affected the tip width and pore size of the nanowall networks. The z-profile Raman spectroscopy measurements revealed the GaN nanowall network retained the same strain present in the GaN template. The optical properties of these GaN nanowall networks have been studied using photoluminescence and ultrafast spectroscopy and an enhancement of optical band gap has been observed for the nanowalls having a tip width of 10-15 nm due to the quantum carrier confinement effect at the wall edges. The electronic structure of the GaN nanowall networks has been studied using X-ray photoemission spectroscopy and it has been compared to the GaN template. The calculated Ga/N ratio is largest ($2) for the GaN nanowall network grown at 30 Hz. Surface band bending decreases for the nanowall network with the lowest tip width. The homoepitaxial growth of porous GaN nanowall networks holds promise for the design of nitride based sensor devices.

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“…The wafer cleaning consists of a solvent clean (de-ionised water, trichloroethylene, acetone and isopropanol), followed by a de-oxidation step (boiling aqua regia) and finally a dip in boiling ammonia-polysulfide solution to passivate the surface [2,3]. The wafers are then loaded into an electron beam evaporator to deposit the mirror metallisation: 3 nm of palladium (Pd), 100 nm of silver (Ag), 30 nm of nickel (Ni) and 300 nm of gold (Au).…”

Section: Device Designmentioning

confidence: 99%

Fabrication of GaN-Based Resonant Cavity LEDs

Maaskant

Akhter

Roycroft

et al. 2002

phys. stat. sol. (a)

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This article describes a fabrication process for GaN based resonant cavity (RC) LEDs. The devices emit through the transparent sapphire substrate. An AlGaN/GaN DBR forms the bottom mirror, while a PdAg‐based p‐contact metallisation serves as top mirror. The PdAg mirrors have been characterized optically by reflectometry, and electrically by circular TLM measurements. A specific contact resistivity of 1.0 × 10—2 Ωcm2 has been measured, without any annealing of the contacts. For the GaN to PdAg interface a reflectivity of 60% has been measured for a wavelength of 510 nm. At 20 mA bias the RC‐LEDs show a forward voltage of 3.5 V and an optical output of 330 μW through the back of the wafer.

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X-ray photoelectron spectroscopy study of (NH4)2Sx-treated Mg-doped GaN layers

Cited by 53 publications

References 10 publications

Low resistive ohmic contact formation on surface treated-n-GaN alloyed at low temperature

Low resistive ohmic contact formation on surface treated-n-GaN alloyed at low temperature

Structural, optical and electronic properties of homoepitaxial GaN nanowalls grown on GaN template by laser molecular beam epitaxy

Fabrication of GaN-Based Resonant Cavity LEDs

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