Hydrogen sensitivity of InP HEMTs with a thick Ti-layer in the Ti/Pt/Au gate stack

S. D. Mertens, J. A. Del Alamo, T. Suemitsu, T. Enoki

Research output: Contribution to journalConference articlepeer-review

2 Citations (Scopus)


We have investigated the hydrogen sensitivity of InP HEMTs with a gate stack containing a thick Ti-layer (order of 1000 Å). We have found that the hydrogen-induced piezoelectric effect in these devices is an order of magnitude smaller than conventional Ti/Pt/Au-gate HEMTs with a thin Ti layer (order of 250 Å). This markedly improved reliability can be explained through the diffusion mechanism of H in Ti which limits hydrogenation of the Ti layer to a thin sheet at the top. Using Auger Electron Spectroscopy, we have confirmed that under the studied conditions, TiHx is only formed in the top 250 Å of the Ti-layer. In some devices located in the periphery of the wafer, we have observed a second hydrogen degradation mechanism that induces a large positive ΔVT. This appears to be related to an improperly fabricated gate recess. The use of a thick Ti layer in the gate stack allows for a simple and effective mitigation of the H-induced piezoelectric effect in InP and other III-V HEMTs.

Original languageEnglish
Pages (from-to)223-226
Number of pages4
JournalConference Proceedings - International Conference on Indium Phosphide and Related Materials
Publication statusPublished - 2003 Jul 28
Externally publishedYes
Event2003 International Conference Indium Phosphide and Related Materials - Santa Barbara, CA, United States
Duration: 2003 May 122003 May 16

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering


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