Special Issue on the nano devices 서울대 나노 협동과정 & 나노 응용시스템 연구센터 (NSI_NCRC) The 5th lecture: MOS as the sensor Prof. Young June Park

MOSFET Structures and challenges in scaling

Motivation : Other Alternatives

Motivation: Evolution of DG FET(or FINFET) 5nm-Gate Nanowire FinFET Fu-Liang Yang, et., TSMC group, SOVT 2004

FET as the chemical sensor(with gate)

2 Types: with gate and without gate jlkj jlkj -With gate: based on the ISFET structure changing the charge of the insulator –electrolyte interface through : by changing the pH of the electrolyte or by direct binding of the receptor-molecule binding -Nanowire conductor(either silicon or CNT where gate is not existent) : in this case, surface potential of the conductor should be stabilized, or the conductor should not be of the surface type device.

Based on ISFET(pH sensitve) -The interface between the Insulator and electrolyte Is modified by the pH of the Electrolyte, which in turn is modulated by the bio chemical reaction In the insulator -In order to achieve better sensitivity, Al2O3, Si3O4, or Ta2O5 are used.

- Due to the reaction between the enzyme(as the bioreceptor) and the target material, Products(usually H+) are generated which change the local solution concentration, which in turn is detected by the ISFET. Enzymes are bound to gate insulator through : -physical or chemical adsorption -entrapment within polymeric matrices -cross-linking through cross-linking agents ISFET based sensor type 1: Enzyme FET

- Changes monitored by the ISFET include Extracellular pH, ion concentration,O2 consumption, CO2production, redox potential, other metabolic products, neuronal potentials and others. -Even the activation of the cell can be Performed by MOSFET driven electrode. ISFET based sensor type 1: Cell FET

Based on ISFET: type 2 -The interface between the Insulator and electrolyte Is modified by the DNA-DNA hybridization or antigen-antibody affinity reaction. -Potential changes is caused by surface polarization effects or through change in dipole moments

Nanowire conductor without gate -In this case, surface of the FET (or conductor) should be stabilized without gate conductor -Stability of the sensor against the environment is the challenge.

Nanowire conductor -Biotin modified nanowires detect streptavidinbinding at picomolar concentrations with reversible antibody binding -To configure nanowire sensor devices for screening small-molecule inhibitors to tyrosine kinases, we linked the kinase Abl to the surface of Si nanowire FETs and investigated the binding of ATP and competitive inhibition of ATP binding with organic molecules, such as the drug Gleevec®, as shown schematically i

Nanowire conductor as the drug discovery -Even nanowire FET is applied to the drug discovery by, for example, screening small-molecule inhibitors to tyrosine kinases. -Link the kinase Abl to the surface of Si nanowire FETs and investigated the binding of ATP And competitive inhibition of ATP binding with organic molecules, which is the target materials to find. i Fernando Patolsky and Charles M. Lieber*, from April, Materialtoday