Performance of InGaN-Based Thin-Film LEDs With Flip-Chip Configuration and Concavely Patterned Surface Fabricated on Electroplating Metallic Substrate

Hu, Xiaolong; Qi, Zhao-yi; Hong, Wei; Zhang, Xichun

doi:10.1109/jphot.2016.2516911

Cited by 4 publications

(5 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…An improvement in efficiency has been previously demonstrated on VTF-LEDs released through laser lift-off, where the defective undoped GaN buffer layer is removed through a backside etching process. 10,36 Work is in progress to optimize this step for the SLOT process. Optical simulation was also conducted to investigate the effect of the n-AlGaN layer on the LEE and far field angular emission pattern (FFP) of the VTF-LEDs.…”

Section: ■ Resultsmentioning

confidence: 99%

“…Either dry or wet AlGaN etch must be conducted on the free-standing membrane, which is challenging and requires further adaptation. An improvement in efficiency has been previously demonstrated on VTF-LEDs released through laser lift-off, where the defective undoped GaN buffer layer is removed through a backside etching process. , Work is in progress to optimize this step for the SLOT process. Optical simulation was also conducted to investigate the effect of the n -AlGaN layer on the LEE and far field angular emission pattern (FFP) of the VTF-LEDs.…”

Section: Resultsmentioning

confidence: 99%

“…This work also opens new ways for the fabrication of thin-film flip-chip (TFFC) LEDs, where both contacts are placed on the backside of the LED. Such a configuration , allows for higher light extraction (no metal is deposited on the emitting side and there is no requirement of wire-bonding to access the n -contact). TFFC-LEDs can be achieved through the SLOT process, by introducing additional process steps while still maintaining the LED structure on the h-BN/sapphire native substrate.…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Monolithic Free-Standing Large-Area Vertical III-N Light-Emitting Diode Arrays by One-Step h-BN-Based Thermomechanical Self-Lift-Off and Transfer

Karrakchou

Gujrati

Vuong

et al. 2021

ACS Appl. Electron. Mater.

View full text Add to dashboard Cite

We demonstrate the fabrication of vertical InGaN light emitting diodes on large-area freestanding membranes, using a mechanical lift-off technique enabled by 2D h-BN. 30-μm-thick electroplated copper deposited on the epilayer (i) gives rigidity to the structure, preventing crack generation, (ii) functions as a back mirror and as a heat sink, and (iii) enables one-step self-lift-off and transfer of LED structures from h-BN/sapphire during a thermal treatment at 100°C. Free-standing arrays of LEDs on thick membranes were processed and their electro-optical performance characterized. This approach can provide a solution for the fabrication of low cost, wafer scale, crack-free, and highly reproducible free-standing arrays of vertical LEDs with up to centimeter-size areas.

show abstract

Section: ■ Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Monolithic Free-Standing Large-Area Vertical III-N Light-Emitting Diode Arrays by One-Step h-BN-Based Thermomechanical Self-Lift-Off and Transfer

Karrakchou

Gujrati

Vuong

et al. 2021

ACS Appl. Electron. Mater.

View full text Add to dashboard Cite

show abstract

“…The phosphor is therefore either attached to the sapphire or to the die in form of a ceramic based platelet or as silicon-based layer. The removal of the sapphire improves optical performance and reduces the phosphor temperature due to direct thermal connection to the die [7]. The roughly 100μm thick sapphire and the phosphor containing ceramic platelet act as additional stiffener for the die and can be beneficially for thermo-mechanical reliability.…”

Section: A Ledsmentioning

confidence: 99%

Investigations on High-Power LEDs and Solder Interconnects in Automotive Application: Part I—Initial Characterization

Schmid

Zippelius

Hanß

et al. 2022

IEEE Trans. Device Mater. Relib.

View full text Add to dashboard Cite

Thermo-mechanical reliability is one major issue in solid-state lighting. Mismatches in the coefficients of thermal expansion (CTE) between high-power LED packages and substrates paired with temperature changes induce mechanical stress. This leads to a thermal degradation of LED modules by crack formation in the solder interconnect and/or delamination in the substrate, which in turn increases junction temperature and thus decreases light output and reduces lifetime. To investigate degradation and understand influence of LED package design and solder material, a reliability study with a total of 1800 samples − segmented in nine LED types and five solder pastes − is performed. First of all, in this paper a state-of-the-art review of high-power LED packages is performed by analyzing and categorizing the packaging technologies. Second, the quality inspection after assembly is realized by transient thermal analysis (TTA), scanning acoustic microscopy (SAM) and X-ray. For TTA, a new method is introduced to separate the thermal resistance of the LED package from solder interconnect and substrate by applying the transient dual interface method (TDI) on samples with different solder interconnect void ratios. Further measurement effort is not required. The datasheet values for thermal resistance are verified and the different LED package types are benchmarked. The void ratio of the solder interconnects is determined by X-ray inspection combined with an algorithm to suppress disruptive internal LED package structures. TTA and TDI revealed that initial thermal performance is independent of solder paste type and that voiding is more critical to smaller LED packages. In addition, lower silver proportion in the paste is found to increase voiding. SAM is less sensitive for initial void detection than Xray, but it's applied to monitor crack propagation while aging in combination with TTA. The results of the reliability study, i.e., the crack growth under temperature shock test for the different SAC solders, will be presented in a second independent paper.

show abstract

“…An important demand on these device applications is high light extraction efficiency (LEE) which is vital, in particular, for lightening applications. Many different epitaxial layer designs as well as the different device configurations have been employed to increase LED LEE [3][4][5][6]. One of the most common InGaN/GaN LED device configurations is the conventional top emitting LEDs (TE LEDs) which include a variety of top current spreading layers, such as thin Ni/Au metallization, ITO, AZO and etc., and interdigitated metal contact based structures [7].…”

Section: Introductionmentioning

confidence: 99%

Distributed contact flip chip InGaN/GaN blue LED; comparison with conventional LEDs

Genç

Шеремет

Elçi

et al. 2019

Superlattices and Microstructures

View full text Add to dashboard Cite

This paper presents high performance, GaN/InGaN-based light emitting diodes (LEDs) in three different device configurations, namely Top Emitting (TE) LED, conventional Flip Chip (FC) and Distributed Contact (DC) FC. Series resistances as low as 1.1 Ω have been obtained from FC device configurations with a back reflecting ohmic contact of Ni/Au/RTA/Ni/Ag metal stack. A small shift has been observed between electroluminescence (EL) emissions of TE LED and the FC LEDs. In addition, FWHM value of the EL emission of DCFC LED has shown the minimum value of 160 meV (26.9 nm). Furthermore, DCFC LED configuration has shown the highest quantum efficiency and power output, with 330 mW at 500 mA current injection, compared to that of traditional wire bonded TE LEDs and the conventional FC LEDs.

show abstract

Performance of InGaN-Based Thin-Film LEDs With Flip-Chip Configuration and Concavely Patterned Surface Fabricated on Electroplating Metallic Substrate

Cited by 4 publications

References 21 publications

Monolithic Free-Standing Large-Area Vertical III-N Light-Emitting Diode Arrays by One-Step h-BN-Based Thermomechanical Self-Lift-Off and Transfer

Monolithic Free-Standing Large-Area Vertical III-N Light-Emitting Diode Arrays by One-Step h-BN-Based Thermomechanical Self-Lift-Off and Transfer

Investigations on High-Power LEDs and Solder Interconnects in Automotive Application: Part I—Initial Characterization

Distributed contact flip chip InGaN/GaN blue LED; comparison with conventional LEDs

Contact Info

Product

Resources

About