Nlt Technologies, Ltd.

Seiya Kobayashi

Kazushige Takechi

Shinnosuke Iwamatsu

Toru Yahagi

Yoshiyuki Watanabe

Hiroshi Haga

Yutaka Abe

The ion sensors using TFT or MOSFET are low in the measurement sensitivity so that it is difficult to detect an extremely small amount of sensing-target substance. A TFT ion sensor includes both a gate electrode (a silicon substrate) and a reference electrode, in which the electrostatic capacitance of a gate insulating film (a thermal oxide film) is set to be larger than the electrostatic capacitance of an ion sensitive insulating film. Therefore, it is possible to detect the concentration of ions, hormones, and the like in a sensing-target substance from the shift in the threshold voltage of the gate-source voltage to source-drain current property.

TFT ion sensor and TFT ion sensor apparatus using the same

With a TFT using an oxide semiconductor film, there is such an issue that oxygen deficit is generated in a surface region of the oxide semiconductor film after performing plasma etching of a source/drain electrode, thereby increasing the off-current. Provided is a TFT which includes: a gate electrode on an insulating substrate; a gate insulating film on the gate electrode; an oxide semiconductor film containing indium on the gate insulating film; and a source/drain electrode on the oxide semiconductor film. Further, the peak position derived from an indium 3d orbital in the XPS spectrum of a surface layer in a part of the oxide semiconductor film where the source/drain electrode is not superimposed is shifted towards a high energy side than the peak position derived from the indium 3d orbital in the XPS spectrum of an oxide semiconductor region existing in a lower part of the surface layer.

Thin film device and manufacturing method thereof

Growing community of inventors

Yamagata, Japan

Seiya Kobayashi