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Nanostructured Double-Gate Ion-Sensitive Field-Effect Transistor

IP.com Disclosure Number: IPCOM000249371D
Publication Date: 2017-Feb-22
Document File: 5 page(s) / 1M

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a double-gate ion-sensitive field-effect transistor (DG-ISFET) bio-sensor having a nanostructured channel and fabrication method, wherein the said nanostructures are sublithographic, in some embodiments. The disclosed nano-structures increase the surface-to-volume ratio of the sensor and therefore increase the sensitivity of the biosensor compared to a flat sensor surface.

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Nanostructured Double -Gate Ion-Sensitive Field -Effect Transistor

Double-gate ion-sensitive field-effect transistor (DG-ISFET) bio-sensors have been proposed for enhanced the sensitivity [1-3]. Compared to a single-gate ISFET, the sensitivity of the DG-ISFET can be enhanced by up to the ratio of the gate dielectric capacitors of the top gate to that of the bottom gate . Therefore, in appropriate design, a thin (and high-k) dielectric for the top gate and a relatively thick (and lower-k) dielectric for the bottom gate (e.g., the buried oxide (BOX) in Silicon on Insulator (SOI) substrate) can substantially increase the sensitivity. Also in an appropriate design, the sensitivity can be further enhanced by choosing a thin -body and lightly-doped (or substantially undoped) SOI substrate. Nevertheless, the sensitivity limitations inherent to planar (flat) sensor surfaces apply to the disclosed hybrid sensor .

The novel contribution is a double-gate ion-sensitive field-effect transistor (DG-ISFET) bio-sensor having a nanostructured channel and fabrication method , wherein the said nanostructures are sublithographic, in some embodiments. The disclosed nano-structures increase the surface-to-volume ratio of the sensor and therefore increase the sensitivity of the biosensor compared to a flat sensor surface .

The sensor is comprised of inorganic semiconductor nano -channels disposed between a source and a drain on a buried insulator (e.g., BOX), a thin (and preferably high-k) dielectric disposed onto the surface of the inorganic nano -channels, and at least a portion of the inorganic nano-channels is functionalized by bio-sensing elements. The bio-sensor further includes a back-gate electrically coupled to the channel via the said buried insulator. The method of forming the nano -structured channel includes the formation of an initial fin on the buried insulator , growth of a digital alloy on the said initial fin, chemical-mechanical polishing, and selective etching of one of the two elements of the digital alloy (preferably that of the initial fin) with respect to the other one.

Figure 1: Novel structure

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The following figures repre...