Silicon Nitride-induced Threshold Voltage Shift in p-GaN HEMTs with Au-free Gate-first Process

Yi Cheng Chen, Shun Wei Tang, Pin Hau Lin, Zheng Chen Chen, Ming Hao Lu, Kuo Hsing Kao, Tian Li Wu*

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

In this work, we observe the distinct VTH characteristics in the Au-free gate-first processing p-GaN/AIGaN/GaN HEMTs with two commonly used passivation layers, i.e., SiN and SiO2. The device with SiN shows a depletion-mode (D-mode) characteristic (VTH ∼ -5V) whereas the device with SiO2 passivation exhibits an enhancement-mode (E-mode) characteristic (VTH ∼ +0.7V). Furthermore, Transmission Line Measurement (TLM) devices are fabricated to investigate the effects of the passivation on two dimensional electron gas (2DEG) in p-GaN/AIGaN/GaN stack. The results indicate that a low Rsh is obtained while passivating device surface with SiN layer, suggesting that 2DEG is present, which is most probably due to an unfunctional p-GaN layer. The SIMS results indicate a high H-intensity in the p-GaN/AIGaN/GaN stack with a SiN passivation layer. Thus, P-GaN deactivation due to the formation of complex Mg-H after SiN passivation is proposed to explain the D-mode characteristic in the device with a SiN passivation layer.

Original languageEnglish
Title of host publication2020 IEEE International Symposium on the Physical and Failure Analysis of Integrated Circuits, IPFA 2020
PublisherInstitute of Electrical and Electronics Engineers Inc.
ISBN (Electronic)9781728161693
DOIs
StatePublished - 20 Jul 2020
Event2020 IEEE International Symposium on the Physical and Failure Analysis of Integrated Circuits, IPFA 2020 - Singapore, Singapore
Duration: 20 Jul 202023 Jul 2020

Publication series

NameProceedings of the International Symposium on the Physical and Failure Analysis of Integrated Circuits, IPFA
Volume2020-July

Conference

Conference2020 IEEE International Symposium on the Physical and Failure Analysis of Integrated Circuits, IPFA 2020
CountrySingapore
CitySingapore
Period20/07/2023/07/20

Keywords

  • Au-free
  • p-GaN HEMTs
  • passivation
  • SiN
  • SiO2
  • threshold voltage shift

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