High efficiency and improved ESD characteristics of GaN-based LEDs with naturally textured surface grown by MOCVD

Tsai, Chi-Ting; Sheu, Jinn-Kong; Wang, P.T.; Lai, Wei Chih; Shei, Shih–Chang; Chang, Shoou‐Jinn; Kuo, Chih-Hung; Kuo, Chia Wei; Su, Yan–Kuin

doi:10.1109/lpt.2006.875063

Cited by 68 publications

(17 citation statements)

References 5 publications

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“…Using Antiparallel Ga-and N-Polar Domains in p-GaN Layer [7], [8]; varying the p-GaN layer growth temperature [6]; developing modulation-doped AlGaN-GaN superlattice structures [9]; and varying the internal-capacitance structure of the LED [10]. We are unaware, however, of any reports describing the relationship between the p-layer polarity and the ESD properties of nitride-based LEDs.…”

Section: Improvement Of Esd Level Of Gan-based Ledsmentioning

confidence: 99%

“…One possibility is the relaxation of the strain. The relatively low growth temperature (840 • C) and heavy Si doping concentration (1 × 10 19 atoms cm −3 ) of the underlying space layer enhance the formation of V-shaped pits, which can be attributed to the small diffusion length of the Ga atom that hinders its migration to the proper location at low temperature [7]. A high-resolution X-ray diffraction θ/2θ scan did reveal a larger Bragg angle θ position (17.373 • ) shifting to the higher angle side for sample B, compared with that for sample A (17.346 • ), indicating that a larger tensile stress prevails in sample B [19].…”

Section: Improvement Of Esd Level Of Gan-based Ledsmentioning

confidence: 99%

“…4(b), resulting in the high ESD endurance. Another effect that introducing a thicker space layer may suppress the formation of V-shaped pitrelated TDs with their dislocations penetrating to the p-layer region should not be excluded in reasoning the improvement of the ESD level [7]. The proposed model in Fig.…”

Section: (A)]mentioning

confidence: 99%

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Improvement of ESD Level of GaN-Based LEDs Using Antiparallel Ga- and N-Polar Domains in p-GaN Layer

Huang

Hong

Chou

2011

IEEE Electron Device Lett.

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Electrostatic discharge (ESD) endurance ability of InGaN blue light-emitting diodes is significantly improved when antiparallel Ga-and N-polar domains coexist within the p-type GaN-layer region. The inversion of Ga to N polarity in this region, which is verified using convergent-beam electron diffraction, was induced by the stress accumulated in the underlying layers. A typical p-type GaN layer, which is composed of a periodical arrangement of Ga-polar domains (width, 450 nm) and antiparallel Ga-and N-polar domains (width, 150 nm), improves the negative human-body mode ESD 4000 V pass yields to greater than 90%.Index Terms-Antiparallel domain, electrostatic discharge (ESD), InGaN light-emitting diode (LED), p-type GaN layer. N ITRIDES are semiconductors possessing wide and direct energy gaps. They have attracted much interest as materials for use in short-wavelength optoelectronic and high-temperature electronic applications, such as visible lightemitting diodes (LEDs), laser diodes, and photodetectors. Because nitride-based LEDs are applied in traffic signals, backlight units, and general lighting, their reliability is an important issue. In particular, the electrostatic discharge (ESD) stress, which induces latent damage or sudden failure in LED devices, is now one of the most important product specifications of LEDs. The high density of inherent threading dislocations in GaN-based layers grown on lattice-mismatched and insulating sapphire substrates makes these LEDs susceptible to the generation of poor ESD properties during the device encapsulation process. Several attempts have been made to improve the ESD properties of GaN-based LEDs, including combining the LEDs with internal Schottky diodes [1], internal protection diodes [2], [3], or a metal-oxide-semiconductor capacitor [4]; inserting a floating metal ring in the LEDs [5]; employing a device bonding-pad design [6] or thicker p-GaN or p-AlGaN layers Manuscript [7], [8]; varying the p-GaN layer growth temperature [6]; developing modulation-doped AlGaN-GaN superlattice structures [9]; and varying the internal-capacitance structure of the LED [10]. We are unaware, however, of any reports describing the relationship between the p-layer polarity and the ESD properties of nitride-based LEDs.In this letter, we achieved a significant improvement in the ESD properties of an LED through the growth of an elaborate bundle of antiparallel Ga-and N-polar domains within the p-type GaN layer region. We have also developed a plausible model to explain this improvement in the ESD properties.The epitaxial layers of the InGaN LED were grown on (0001) patterned sapphire substrates in a vertical close-coupled showerhead rotating-disk reactor (Thomas Swan Scientific Equipment, Cambridge, U.K.). A 30-nm-thick buffer layer was grown at 550 • C, and then, a 1.5-μm-thick undoped GaN layer, a 5-μm-thick Si-doped GaN n-type layer, and a 10-nm-thick n-type AlGaN cladding layer were grown at 1040 • C. Next, a 260-(sample A) or 460-nm-thick (sample B) heavily Si-doped GaN space layer ...

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Section: Improvement Of Esd Level Of Gan-based Ledsmentioning

confidence: 99%

Section: Improvement Of Esd Level Of Gan-based Ledsmentioning

confidence: 99%

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Improvement of ESD Level of GaN-Based LEDs Using Antiparallel Ga- and N-Polar Domains in p-GaN Layer

Huang

Hong

Chou

2011

IEEE Electron Device Lett.

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“…Moreover, few studies have proposed anti-ESD strategies for photoelectric components, in particular, GaN-based LEDs. Studies on GaN-based LEDs have recommended establishing and incorporating a parallel protection diode [20]- [23], Schottky diode [24], [25], extra capacitor [26]- [28], n or undoped GaN layers [29]- [32], textured p-GaN layers [33]- [35], super-lattice structures [36]- [39], floating metal rings [40], bottom metal air-gap structures [41], or additional CMOS protection circuits [42]. However, these strategies involve additional layers and increased costs.…”

Section: Introductionmentioning

confidence: 99%

Enhanced Electrostatic Discharge Reliability in GaN-Based Light-Emitting Diodes by the Electrode Engineering

Chen

2014

J. Display Technol.

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In this study, the electrode structure of Gallium nitride (GaN)-based light-emitting diodes (LEDs) was investigated to improve their antielectrostatic discharge (anti-ESD) ability. The test results indicated that a strong correlation exists between the ESD immunity level of GaN-based blue LEDs and their electrode structure. The proposed LED design features a long parallel extension of the p-and n-electrode areas to facilitate the uniform distribution of ESD current and enhance the anti-ESD abilities. Compared with the standard reference group, the antireverse and antiforward modes of ESD in the experimental group were, respectively, 29% and 171% more than those in a standard reference group, which could enhance the reverse-mode and forwardmode ESD immunity of GaN-based LEDs. Therefore, using LEDs based on the optimal design of p-and n-electrode areas is an excellent strategy for enhancing anti-ESD ability without altering processing conditions. Index Terms-Electrostatic discharge (ESD), forward-mode, human-body model (HBM), metal-organic chemical vapor deposition (MOCVD), multiquantum well (MQW), reverse-mode, secondary breakdown current, transmission-line pulsing (TLP).

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“…To form surface texture pattern, several techniques are applied, such as anisotropic photoelectrochemical etching process (Fujii et al 2004), natural lithography (Yang et al 2005). These techniques make LED surface roughened in shape of trapezia (Han et al 2006), pyramid (Fujii et al 2004) and V-shaped (Tsai et al 2006), Surface roughness is critical and must be controlled by about one-half wavelength according to (Yang et al 2005). The dimension of a single texture unit varies near LED peak wavelength (Windisch et al 1999).…”

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confidence: 99%

Simulation for light power distribution of 3D InGaN/GaN MQW LED with textured surface

Cheng

Yang²,

Xia³

et al. 2011

Opt Quant Electron

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In this paper, we introduce a full 3D simulation for light power distribution of an InGaN/GaN MQW LED with a textured surface. Device simulation was performed with the APSYS software to get power distribution of light sources inside the LED. Based on this, ray tracing simulation was carried out to get light power distribution outside the LED. During the process of ray tracing, the textured surface was treated as a special material interface whose reflectivity, transmittance and refraction angle are obtained with a Finite-Difference Time-Domain (FDTD) method instead of using the usual Fresnel formulas for normal material interfaces. By comparing the ray tracing results with and without the textured surface, we found that the textured surface yields a smoother transmitted power distribution and greatly improved power extraction efficiency, which are comparable to experiment. These effects may be further improved by optimizing the texture geometry.

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High efficiency and improved ESD characteristics of GaN-based LEDs with naturally textured surface grown by MOCVD

Cited by 68 publications

References 5 publications

Improvement of ESD Level of GaN-Based LEDs Using Antiparallel Ga- and N-Polar Domains in p-GaN Layer

Improvement of ESD Level of GaN-Based LEDs Using Antiparallel Ga- and N-Polar Domains in p-GaN Layer

Enhanced Electrostatic Discharge Reliability in GaN-Based Light-Emitting Diodes by the Electrode Engineering

Simulation for light power distribution of 3D InGaN/GaN MQW LED with textured surface

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