Improved sensing characteristics of MISiC Schottky-diode hydrogen sensor by using HfO2as gate insulator

Wing Man Tang, C. H. Leung, P. T. Lai

Research output: Journal article publicationJournal articleAcademic researchpeer-review

7 Citations (Scopus)


Hafnium dioxide deposited by RF sputtering is used as the gate insulator of metal-insulator-silicon-carbide (MISiC) Schottky-diode hydrogen sensors. Sensors with different gate insulator thicknesses are fabricated for investigation. Their hydrogen-sensing properties are compared with each other by taking measurements at various temperatures and hydrogen concentrations using a computer-controlled measurement system. Experimental results show that for the same insulator thickness, the HfO2sensor is more sensitive than its SiO2counterpart. This should be mainly attributed to the larger barrier-height at the Pt/HfO2interface which can reduce the current of the sensor before hydrogen exposure. Moreover, the sensitivity initially increases with the thickness of the HfO2film because a thicker oxide layer can provide a larger barrier-height reduction upon hydrogen exposure. However, further increasing the thickness of the HfO2dielectric beyond about 3.3 nm reduces the sensitivity, possibly due to more trapped charges in thicker high-k dielectric which can screen the effect of the polarized hydrogen layer.
Original languageEnglish
Pages (from-to)1780-1785
Number of pages6
JournalMicroelectronics Reliability
Issue number11-12
Publication statusPublished - 1 Nov 2008
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics
  • Safety, Risk, Reliability and Quality
  • Surfaces, Coatings and Films
  • Electrical and Electronic Engineering

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