A tantalum diffusion barrier layer for improving the output performance of AlGaInP-based light-emitting diodes

Dae Hyun Kim, Jae Seong Park, Daesung Kang, Tae Yeon Seong

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2 Citations (Scopus)

Abstract

We have investigated the effect of a Ta diffusion barrier layer on the electrical characteristics of AuBe/Au contacts on a p-GaP window layer for AlGaInP-based light-emitting diodes (LEDs). It was shown that after annealing at 500 C, the AuBe/Ta/Au contacts exhibited nearly 2 orders of magnitude lower specific contact resistance (2.8×106?cm2) than the AuBe/Au contacts (1.0×10%4?cm2). The LEDs with and without the Ta diffusion barrier layer showed an external quantum efficiency of 14.03 and 13.5% at 50 mA, respectively. After annealing at 500 C, the AuBe/Ta/Au contacts showed a higher reflectance (92.8% at 617 nm) than that of the AuBe/Au contacts (87.7%). X-ray photoemission spectroscopy (XPS) results showed that the Ga 2p core level for the annealed AuBe/Au samples shifted to higher binDing energies, while this level shifted towards lower binDing energies for the AuBe/Ta/Au samples. Depth profiles using Auger electron spectroscopy (AES) showed that annealing of the AuBe/Au samples caused the outdiffusion of both Be and P atoms into the metal contact, while for the AuBe/Ta/Au samples, the outdiffusion of Be atoms was blocked by the Ta barrier layer and more Be atoms were indiffused into GaP. The annealing-induced electrical degradation and ohmic contact formation are described and discussed based on the XPS and electrical results.

Original languageEnglish
Article number032102
JournalJapanese Journal of Applied Physics
Volume55
Issue number3
DOIs
Publication statusPublished - 2016 Mar 1

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)

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