Ir/Ag reflector for high-performance GaN-based near UV light emitting diodes

Ban, Keun-Yong; Hong, Hyun Gi; Noh, Do Young; Sohn, Jung Inn; Kang, Dae Joon; Seong, Tae Yeon

doi:10.1016/j.mseb.2006.04.045

Cited by 9 publications

(9 citation statements)

References 19 publications

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“…However, Ag can agglomerate during annealing, leading to degradation in electrical and optical properties. To overcome this problem, several research groups have investigated different multimetal contacts, such as Ir/Ag [ 2 ], Ni/Ag [ 3 ], Ni/Au/Ag [ 4 ], and transparent conductive oxide/Ag contacts, such as ITO/Ag [ 5 ], CIO/Ag [ 6 ], and ZIO/Ag [ 7 ]. In addition, different Ag alloys, such as Ag–Al [ 8 ], Ag–Cu [ 1 ], and Ag–Mg alloys [ 9 ], have been investigated as p-GaN contacts and have been proven to suppress agglomeration.…”

Section: Introductionmentioning

confidence: 99%

Optimization of annealing conditions for Ag/p–GaN ohmic contacts

Pan

et al. 2021

Appl. Phys. A

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The electrical and optical properties of Ag/p–GaN contacts have been investigated as a function of the annealing temperature, oxygen concentration, and annealing time. Specific contact resistance ( ρ c ) values as low as 1.2 × 10 –4 Ω·cm 2 were obtained from the Ag/p–GaN contact annealed at 400 °C for 60 s in ambient O 2 /N 2 (1:10). We found that the participation of oxygen improves the formation of ohmic contacts. Oxygen might remove the H in Mg–H complexes to activate the Mg acceptors and enhance Ga out-diffusion to form an Ag–Ga solid solution. We also found that the reflectivity of the Ag layer decreases with increasing annealing temperature in the O 2 -containing ambient environment. Thus, an optimal annealing condition of Ag/p–GaN for blue and green LEDs is suggested based on these results. We also used the suggested annealing conditions to form ohmic contacts on DUV LEDs and achieved good electrical performance. The forward voltages of UVC LEDs fabricated with annealed Ag contacts were 6.60 V (7.66 V) at a 40 mA (100 mA) injection current.

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Section: Introductionmentioning

confidence: 99%

Optimization of annealing conditions for Ag/p–GaN ohmic contacts

Pan

et al. 2021

Appl. Phys. A

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“…Accordingly, two kinds of p-type ohmic contact with high reflectivity and low contact resistance have been investigated to develop low-resistance ohmic contacts to p-type GaN with light reflectance to achieve high light-extraction efficiency FCLEDs. The first one is based on the multi-metal contact, such as Ir/Ag [9], Pd/Ni/Al/Ti/Au [10], Ni/Ag/Au [11] and Ni/Au/Rh [12]; the other is based on transparent conductive oxide (TCO)/Ag contact, such as MIO/Ag [13] and ICO/Ag [14]. In the Ir/Ag contacts [9], the specific contact resistance and the reflectivity are about 3.26 × 10 −4 cm 2 and 70-80%, respectively.…”

Section: Introductionmentioning

confidence: 99%

“…The first one is based on the multi-metal contact, such as Ir/Ag [9], Pd/Ni/Al/Ti/Au [10], Ni/Ag/Au [11] and Ni/Au/Rh [12]; the other is based on transparent conductive oxide (TCO)/Ag contact, such as MIO/Ag [13] and ICO/Ag [14]. In the Ir/Ag contacts [9], the specific contact resistance and the reflectivity are about 3.26 × 10 −4 cm 2 and 70-80%, respectively. In the Ni-based contacts [10,11], the thickness of the Ni layer must be very thin, such as 0.3-1 nm, to ensure high reflectivity, and the required process is hard to control.…”

Section: Introductionmentioning

confidence: 99%

Ag and zinc oxide-doped indium oxide ohmic contacts to p-type GaN for flip-chip LED applications

Chen¹,

Ho²

2007

J. Phys. D: Appl. Phys.

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This work discusses Ag/zinc oxide-doped indium oxide (ZIO) and ZIO/Ag ohmic contacts to p-GaN for flip-chip light-emitting diode (LED) applications. Optimal conditions for Ag/ZIO and ZIO/Ag contacts are adopted to minimize the specific contact resistance to 1.74 × 10−4 Ω cm2 and 1.15 × 10−3 Ω cm2, respectively, as revealed by the transmission line model after heat treatment at alloying temperatures of 500 °C and 400 °C, respectively, for 10 min in air. Ag/ZIO contacts following treatment at 500 °C yield a reflectance of around 87% at a wavelength of 470 nm. GaN-based LEDs with Ag/ZIO contacts produced forward biases of 3.09 V at an injection current of 20 mA.

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“…10) TiO 2 and SiO 2 are widely used materials for making the backside reflector, and the TiO 2 and SiO 2 thin films are generally fabricated by electron beam (EB) evaporation. [11][12][13][14][15] Unfortunately, the quality of the backside reflector prepared by EB evaporation is limited by its poor film uniformity and accuracy in thickness control. Furthermore, in order to grow an Al mirror on the conventional TiO 2 /SiO 2 DBR, an Al 2 O 3 adhesive layer is usually used to improve the adhesion between Al and the TiO 2 /SiO 2 DBR.…”

mentioning

confidence: 99%

Enhanced Performance of GaN-Based Light-Emitting Diodes by Using Al Mirror and Atomic Layer Deposition-TiO₂/Al₂O₃Distributed Bragg Reflector Backside Reflector with Patterned Sapphire Substrate

Chen

Guo

Zhang

et al. 2013

Appl. Phys. Express

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GaN-based light-emitting diodes (LEDs) coated with an Al mirror and a three-pair TiO 2 /Al 2 O 3 distributed Bragg reflector (DBR) by atomic layer deposition (ALD) grown on a patterned sapphire substrate (PSS) were proposed and realized for the first time. A 43.1% enhancement in light output power (LOP) was realized at 60 mA with the LED coated with an Al mirror and a three-pair ALD-grown TiO 2 /Al 2 O 3 DBR compared with the LED without a backside reflector, as well as a 10.7% enhancement compared with the LED with a conventional Al mirror and a three-pair TiO 2 / SiO 2 DBR reflector. #

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Ir/Ag reflector for high-performance GaN-based near UV light emitting diodes

Cited by 9 publications

References 19 publications

Optimization of annealing conditions for Ag/p–GaN ohmic contacts

Optimization of annealing conditions for Ag/p–GaN ohmic contacts

Ag and zinc oxide-doped indium oxide ohmic contacts to p-type GaN for flip-chip LED applications

Enhanced Performance of GaN-Based Light-Emitting Diodes by Using Al Mirror and Atomic Layer Deposition-TiO₂/Al₂O₃Distributed Bragg Reflector Backside Reflector with Patterned Sapphire Substrate

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Ir/Ag reflector for high-performance GaN-based near UV light emitting diodes

Cited by 9 publications

References 19 publications

Optimization of annealing conditions for Ag/p–GaN ohmic contacts

Optimization of annealing conditions for Ag/p–GaN ohmic contacts

Ag and zinc oxide-doped indium oxide ohmic contacts to p-type GaN for flip-chip LED applications

Enhanced Performance of GaN-Based Light-Emitting Diodes by Using Al Mirror and Atomic Layer Deposition-TiO2/Al2O3Distributed Bragg Reflector Backside Reflector with Patterned Sapphire Substrate

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Enhanced Performance of GaN-Based Light-Emitting Diodes by Using Al Mirror and Atomic Layer Deposition-TiO₂/Al₂O₃Distributed Bragg Reflector Backside Reflector with Patterned Sapphire Substrate