Investigation of AlInN barrier ISFET structures with GaN capping for pH detection

Brazzini, Tommaso and Bengoechea Encabo, Ana and Sánchez García, Miguel Angel and Calle Gómez, Fernando (2013). Investigation of AlInN barrier ISFET structures with GaN capping for pH detection. "Sensors and Actuators B: Chemical", v. 176 ; pp. 704-707. ISSN 0925-4005. https://doi.org/10.1016/j.snb.2012.09.109.

Description

Title: Investigation of AlInN barrier ISFET structures with GaN capping for pH detection
Author/s:
  • Brazzini, Tommaso
  • Bengoechea Encabo, Ana
  • Sánchez García, Miguel Angel
  • Calle Gómez, Fernando
Item Type: Article
Título de Revista/Publicación: Sensors and Actuators B: Chemical
Date: January 2013
ISSN: 0925-4005
Volume: 176
Subjects:
Freetext Keywords: pH sensor; Ion sensitive field effect transistor; AlInN/GaN; 2DEG; Chemical sensor; HEMT
Faculty: E.T.S.I. Telecomunicación (UPM)
Department: Ingeniería Electrónica
Creative Commons Licenses: Recognition - No derivative works - Non commercial

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Abstract

The pH response of GaN/AlInN/AlN/GaN ion-sensitive field effect transistor (ISFET) on Si substrates has been characterized. We analyzed the variation of the surface potential (ΔVsp/ΔpH) and current (ΔIds/ΔpH) with solution pH in devices with the same indium content (17%, in-plane lattice-matched to GaN) and different AlInN thickness (6 nm and 10 nm), and compared with the literature. The shrinkage of the barrier, that has the effect to increase the transconductance of the device, makes the 2-dimensional electron density (2DEG) at the interface very sensitive to changes in the surface.

Although the surface potential sensitivity to pH is similar in the two devices, the current change with pH (ΔIds/ΔpH), when biasing the ISFET by a Ag/AgCl reference electrode, is almost 50% higher in the device with 6 nm AlInN barrier, compared to the device with 10 nm barrier. When measuring the current response (ΔIds/ΔpH) without reference electrode, the device with thinner AlInN layer has a larger response than the thicker one, of a factor of 140%, and that current response without reference electrode is only 22% lower than its maximum response obtained using reference electrode.

More information

Item ID: 15766
DC Identifier: https://oa.upm.es/15766/
OAI Identifier: oai:oa.upm.es:15766
DOI: 10.1016/j.snb.2012.09.109
Official URL: http://www.sciencedirect.com/science/article/pii/S...
Deposited by: Memoria Investigacion
Deposited on: 29 Jun 2013 08:40
Last Modified: 01 Feb 2015 23:56
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