Nlt Technologies, Ltd.

Tianma Japan, Ltd.

Tianma Micro-electronics Co., Ltd.

Shinnosuke Iwamatsu

Kazushige Takechi

Toru Yahagi

Yutaka Abe

Yoshiyuki Watanabe

Mutsuto Katoh

Seiya Kobayashi

Shunsuke Konno

Hiroshi Haga

Hiroki Murayama

Yutaka Murakami

An ion sensing device includes a first field-effect transistor, a second field-effect transistor, a reference electrode configured to directly contact a sample solution, a first ion-sensitive film, and a second ion-sensitive film. Each of the first field-effect transistor and the second field-effect transistor includes a semiconductor film, a bottom gate electrode, a bottom gate insulating film located between the bottom gate electrode and the semiconductor film, and a top gate insulating film. Surface materials in contact with the sample solution for the first ion-sensitive film and the second ion-sensitive films are the same. A sensitivity of the combination of the first field-effect transistor and the first ion-sensitive film is higher than a sensitivity of the combination of the second field-effect transistor and the second ion-sensitive film.

Ion sensing device

An electrostatic sensing device includes a sensor oxide semiconductor TFT, and a controller configured to control the sensor oxide semiconductor TFT. The sensor oxide semiconductor TFT includes an oxide semiconductor active layer, a source electrode connected with the oxide semiconductor active layer, a drain electrode connected with the oxide semiconductor active layer, a gate electrode behind the oxide semiconductor active layer, and a gate insulating layer between the gate electrode and the oxide semiconductor active layer The controller is configured to measure a difference from a reference current of a current flowing between the source electrode and the drain electrode, while applying a driving voltage to the gate electrode, and determine polarity of electrostatic charge of the measurement target based on direction of the difference from the reference current.

Electrostatic sensing device

A TFT biosensor includes a gate electrode (silicon substrate), a reference electrode, and enzyme that is fixed to an insulating substrate spatially separated from the gate electrode and the reference electrode. A pH variation in the vicinity of an ion-sensitive insulating film is induced by a reaction between the enzyme and a sensing object material. The TFT biosensor can detect a concentration of the sensing object material with high sensitivity by detecting the pH variation as a threshold voltage shift of characteristics of a gate-source voltage to a source-drain current.

Biosensor and detection device

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.

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Yamagata, Japan

Shinnosuke Iwamatsu