GaN-Based Light-Emitting Diode With Sputtered AlN Nucleation Layer

Yen, Chih−Hung; Lai, Wei–Chih; Yang, Y. C.; Wang, Chun-Kai; Ko, T.K.; Hon, S. J.; Chang, Shoou‐Jinn

doi:10.1109/lpt.2011.2177654

Cited by 52 publications

(38 citation statements)

References 15 publications

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“…3). The output power enhancement could reach around 52% in magnitude at the emission peak wavelength of 370 nm, but only reach around 6% for GaN-based blue LEDs, as indicated from previous studies [29]. The results imply that the output power of the short-peaked UV wavelength is very sensitive to the dislocation of the u-GaN and n-AlGaN layers.…”

Section: Methodssupporting

confidence: 62%

“…The ex situ nucleation-enabled one-step GaN epitaxy reduces the growth time and thermal cycles of metal organic chemical vapor deposition (MOCVD) epitaxy. Furthermore, we report the one-step growth and high crystal quality of GaN by introducing an ex situ sputtered AlN nucleation layer [29]. In the present study, we demonstrate GaN-based UV LEDs with ex situ sputtered AlN nucleation layers.…”

Section: Introductionmentioning

confidence: 71%

“…The details of the patterned substrate preparation and the ex situ AlN nucleation deposition have already been published elsewhere [29]. During LED epitaxy, trimethylindium, trimethylgallium, trimethylaluminium, and ammonia were used as the source materials of In, Ga, Al, and N, respectively.…”

Section: Methodsmentioning

confidence: 99%

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GaN-Based Ultraviolet Light Emitting Diodes With Ex Situ Sputtered AlN Nucleation Layer

Lai

Yen

Yang

et al. 2013

J. Display Technol.

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We demonstrated the electro-optical characteristics of gallium nitride (GaN)-based ultraviolet (UV) light emitting diodes (LEDs) with sputtered aluminum nitride (AlN) nucleation layer. The introduction of the ex situ sputtered AlN nucleation layer improved the crystal quality of the GaN and the n-AlGaN layer of the GaN-based UV LEDs. Hence, the 20-mA output power of UV LEDs with ex situ AlN nucleation layers is higher than that of UV LEDs with GaN nucleation layers. In addition, the enhanced power output of UV LEDs with ex situ AlN nucleation could reach around 52% in magnitude at peak emission wavelengths of 370 nm compared with power outputs of UV LEDs with GaN nucleation layers. Furthermore, UV LEDs with ex situ AlN nucleation show improved reliability. The UV LEDs with ex situ AlN nucleation layer revealed a power output drop of around 9% within 168 hours, which is less than the around 14% power drop of UV LEDs with GaN nucleation layer. Index Terms-GaN-based ultraviolet light-emitting diodes (UV-LEDs), sputtered AlN, nucleation layer.

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Section: Methodssupporting

confidence: 62%

Section: Introductionmentioning

confidence: 71%

See 1 more Smart Citation

GaN-Based Ultraviolet Light Emitting Diodes With Ex Situ Sputtered AlN Nucleation Layer

Lai

Yen

Yang

et al. 2013

J. Display Technol.

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“…AlN is also widely used as buffer layer for the growth of GaN, in order to reduce the lattice mismatch, stabilize the metal polarity and prevent unwanted reactions between GaN and the substrate [refs. [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Two-step method for the deposition of AlN by radio frequency sputtering

et al. 2013

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This paper presents a detailed study of the influence of deposition conditions on structural and morphological properties of AlN thin films synthesized on c-sapphire substrates by radio frequency (RF) reactive sputtering. After the optimization of deposition parameters such as RF power and substrate temperature, the substrate bias has been identified as a critical variable to improve the structural properties of the AlN layers. The use of negative bias leads to a decrease of the full-width at half-maximum (FWHM) of the rocking curve of the AlN(0002) x-ray reflection and an increase of the grain size. However, 2θ/ω x-ray scans of layers grown under negative bias reveal lattice disorder at the AlN/sapphire interface, which is attributed to the highly accelerated positive ions (Al + , N + , N 2 + ) arriving to the substrate at the initial stages of the deposition process. In order to prevent this interface degradation, we propose a twostep deposition method which consists of starting the growth with an unbiased AlN buffer layer, at least 30 nm thick, followed by AlN deposition under negative bias. This procedure results in high-quality AlN layers with FWHM of the rocking curve of the (0002) reflection of 1.63°, grain size of~40 nm and root-mean-square surface roughness of 0.4 nm.

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“…The nucleation layer between the sapphire substrate and the GaN layer is the key to the dislocation density. Lai et al and Yen et al have employed sputtered AlN nucleation layers in LEDs and achieved improvement of crystal quality [23,24]. In this study, we demonstrate UV-LEDs with a sputtered AlN nucleation layer on PSS.…”

Section: Introductionmentioning

confidence: 74%