Gold-free fully Cu-metallized InGaP/GaAs heterojunction bipolar transistor

Shang Wen Chang*, Edward Yi Chang, Dhrubes Biswas, Cheng Shih Lee, Ke Shian Chen, Chao Wei Tseng, Tung Ling Hsieh, Wei Cheng Wu

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


A gold-free, fully Cu-metallized InGaP/GaAs heterojunction bipolar transistor using platinum as the diffusion barrier has been successfully fabricated. The HBT uses Pd/Ge and Pt/Ti/Pt/Cu for n-type and p+-type ohmic contacts, respectively, and Ti/Pt/Cu for interconnect metals with platinum as the diffusion barrier. The Ti/Pt/Cu structure was stable during annealing up to 350°C judging from the X-ray diffraction (XRD) data and sheet resistance. A current-accelerated stress test was conducted on the device with a current density JC = 140kA/cm2 for 24 h, and the current gain showed no degradation. The devices were also thermally annealed at 250°C for 24h and showed little change. We have successfully demonstrated that an Au-free, fully Cu-metallized HBT can be realized using Pt as the diffusion barrier and Pd/Ge and Pt/Ti/Pt/Cu as the ohmic contacts.

Original languageEnglish
Pages (from-to)8-11
Number of pages4
JournalJapanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers
Issue number1 A
StatePublished - 1 Jan 2005


  • Copper
  • Diffusion barrier
  • GaAs
  • HBT
  • Metallization

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