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Development and fabrication of Ion-sensitive Field Effect Transistor (ISFET) for pH detection, DNA immobilization and hybridization

The fabrication of ion sensitive field-effect transistor (ISFET) using silicon nitride (Si3N4) as the sensing membrane is reported. The operation of ISFET is based on the surface charge adsorption of the membrane-solution interface. This thesis describes the design, fabrication and characterization...

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Main Author: Chong, Soon Weng
Format: Thesis
Language:English
Published: Universiti Malaysia Perlis (UniMAP) 2014
Subjects:
Ion concentration
Ion Sensitive Field Effect Transistor (ISFET)
Ion detection
DNA immobilization
ISFET device
pH detection
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Online Access:http://dspace.unimap.edu.my:80/dspace/handle/123456789/31211
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spelling my.unimap-312112014-01-15T02:02:12Z Development and fabrication of Ion-sensitive Field Effect Transistor (ISFET) for pH detection, DNA immobilization and hybridization Chong, Soon Weng Ion concentration Ion Sensitive Field Effect Transistor (ISFET) Ion detection DNA immobilization ISFET device pH detection Label free The fabrication of ion sensitive field-effect transistor (ISFET) using silicon nitride (Si3N4) as the sensing membrane is reported. The operation of ISFET is based on the surface charge adsorption of the membrane-solution interface. This thesis describes the design, fabrication and characterization of ISFET for pH detection, DNA immobilization and hybridization. Four photomasks were utilized in the fabrication process to create the ISFET device. The fabricated ISFET device was first brought to morphological characterization before proceeding with the electrical characterization. For the analysis of ISFET in test solution, the Ag/AgCl electrode was used as the reference electrode immersed in different values pH buffer. The results were generated by LabTracer 2.0 measurement system which shows that IV characteristic of ISFET devices gives linear response. The acidic pH buffers contains H+ ions which attract more electron into the conduction channel lowering the channel resistance giving higher value of current flow. While the alkaline pH buffers contains OH- ions which pushed away the electrons from the conduction channel generating more positive holes increasing the channel resistance, thus giving a lower value of current flow. When tested with phosphate buffer solution (PBS), the curves show a decreasing trend of drain current with decreasing concentration of the PBS. It was found that the device has a sensitivity of 43.13 mV/pH. The ISFET device has undergo DNA processes after the electrical characterization with pH and PBS. The DNA immobilization and hybridization processes were detected through a drop in the drain current of the device. Prior to DNA immobilization, the silicon nitride surface was chemically modified to enable the ISFET sensing membrane for DNA probes coupling. It was also observed that with decreasing concentration of DNA complimentary targets in the hybridization process has contributed to the decreasing drain current detected. As a conclusion, the silicon nitride ISFET is a flexible device which can be used to detect pH as well as to perform DNA immobilization and hybridization. 2014-01-15T02:02:12Z 2014-01-15T02:02:12Z 2013 Thesis http://dspace.unimap.edu.my:80/dspace/handle/123456789/31211 en Universiti Malaysia Perlis (UniMAP) Institute of Nanoelectronic Engineering
institution Universiti Malaysia Perlis
building UniMAP Library
collection Institutional Repository
continent Asia
country Malaysia
content_provider Universiti Malaysia Perlis
content_source UniMAP Library Digital Repository
url_provider http://dspace.unimap.edu.my/
language English
topic Ion concentration
Ion Sensitive Field Effect Transistor (ISFET)
Ion detection
DNA immobilization
ISFET device
pH detection
Label free
spellingShingle Ion concentration
Ion Sensitive Field Effect Transistor (ISFET)
Ion detection
DNA immobilization
ISFET device
pH detection
Label free
Chong, Soon Weng
Development and fabrication of Ion-sensitive Field Effect Transistor (ISFET) for pH detection, DNA immobilization and hybridization
description The fabrication of ion sensitive field-effect transistor (ISFET) using silicon nitride (Si3N4) as the sensing membrane is reported. The operation of ISFET is based on the surface charge adsorption of the membrane-solution interface. This thesis describes the design, fabrication and characterization of ISFET for pH detection, DNA immobilization and hybridization. Four photomasks were utilized in the fabrication process to create the ISFET device. The fabricated ISFET device was first brought to morphological characterization before proceeding with the electrical characterization. For the analysis of ISFET in test solution, the Ag/AgCl electrode was used as the reference electrode immersed in different values pH buffer. The results were generated by LabTracer 2.0 measurement system which shows that IV characteristic of ISFET devices gives linear response. The acidic pH buffers contains H+ ions which attract more electron into the conduction channel lowering the channel resistance giving higher value of current flow. While the alkaline pH buffers contains OH- ions which pushed away the electrons from the conduction channel generating more positive holes increasing the channel resistance, thus giving a lower value of current flow. When tested with phosphate buffer solution (PBS), the curves show a decreasing trend of drain current with decreasing concentration of the PBS. It was found that the device has a sensitivity of 43.13 mV/pH. The ISFET device has undergo DNA processes after the electrical characterization with pH and PBS. The DNA immobilization and hybridization processes were detected through a drop in the drain current of the device. Prior to DNA immobilization, the silicon nitride surface was chemically modified to enable the ISFET sensing membrane for DNA probes coupling. It was also observed that with decreasing concentration of DNA complimentary targets in the hybridization process has contributed to the decreasing drain current detected. As a conclusion, the silicon nitride ISFET is a flexible device which can be used to detect pH as well as to perform DNA immobilization and hybridization.
format Thesis
author Chong, Soon Weng
author_facet Chong, Soon Weng
author_sort Chong, Soon Weng
title Development and fabrication of Ion-sensitive Field Effect Transistor (ISFET) for pH detection, DNA immobilization and hybridization
title_short Development and fabrication of Ion-sensitive Field Effect Transistor (ISFET) for pH detection, DNA immobilization and hybridization
title_full Development and fabrication of Ion-sensitive Field Effect Transistor (ISFET) for pH detection, DNA immobilization and hybridization
title_fullStr Development and fabrication of Ion-sensitive Field Effect Transistor (ISFET) for pH detection, DNA immobilization and hybridization
title_full_unstemmed Development and fabrication of Ion-sensitive Field Effect Transistor (ISFET) for pH detection, DNA immobilization and hybridization
title_sort development and fabrication of ion-sensitive field effect transistor (isfet) for ph detection, dna immobilization and hybridization
publisher Universiti Malaysia Perlis (UniMAP)
publishDate 2014
url http://dspace.unimap.edu.my:80/dspace/handle/123456789/31211
_version_ 1643796403248431104
score 13.222552

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