Electrical characterization of deoxyribonucleic acid hybridization in metal-oxide-semiconductor-like structures

Abstract

In this work, metal-oxide-semiconductor (MOS)-like sensors in which deoxyribonucleic acid (DNA) strands are covalently immobilized either on Si oxide or on a gold surface were electrically characterized. Si oxide fabrication process allowed us to have a surface insensitive to the solution pH. A significant shift in the flat band voltage was measured after single strand DNA immobilization (+0.47 ± 0.04 V) and after the complementary strand binding (+0.07 ± 0.02 V). The results show that DNA sensing can be performed using a MOS structure which can be easily integrated in a more complex design, thus avoiding the problems related to the integration of micro-electrochemical cells

Optical and Electrical Si-Based Biosensors: Fabrication and Trasduction Issues

“…The probe-anchored sample was obtained performing the immobilization protocol just described and anchoring single strand DNA as probe. The correct DNA immobilization was verified by different techniques [16,17]. A clear shift of the CV characteristics can be observed, suggesting that the DNA negative charge modifies the V FB value.…”

“…The strong deviation from the expected results is due to a high concentration of ions (H + , Na + ) that can migrate from the solution to the semiconductor/dielectric interface. A full discussion can be found [16]. Moreover, the data inspection allowed us to observe that the DNA immobilization causes a visible reduction in the C Min value and the DNA layer thickness can be inferred from these measurement following the calculation assuming a dielectric constant for the biological layer of 3 [29].…”

“…The surface functionalization is most likely to be performed after the device frontend processing, including metal strips and dielectric layers, due to the extreme sensitivity of biological molecules to high temperatures and environments (air, reagent solutions, etc.). It means that the reagents and solutions used to prepare the biosensor surface have not to remove layers (it may occur with metal layers) or change their electrical (or optical) properties as it occurs using silicon dioxide layer as immobilization surface [16]. For the above mentioned reasons we have developed an immobilization protocol able to bind the biological species keeping their functionalities [17] without affecting the device performances.…”

“…For the above mentioned reasons we have developed an immobilization protocol able to bind the biological species keeping their functionalities [17] without affecting the device performances. Moreover, the device architecture must be designed in order to avoid SiO 2 uncovered layers [16,18] during and/or after the functionalization protocol.…”