title: Multi-Wire Tri-Gate Silicon Nanowires Reaching Milli-pH Unit Resolution in One Micron Square Footprint.
abstract: The signal-to-noise ratio of planar ISFET pH sensors deteriorates when reducing the area occupied by the device, thus hampering the scalability of on-chip analytical systems which detect the DNA polymerase through pH measurements. Top-down nano-sized tri-gate transistors, such as silicon nanowires, are designed for high performance solid-state circuits thanks to their superior properties of voltage-to-current transduction, which can be advantageously exploited for pH sensing. A systematic study is carried out on rectangular-shaped nanowires developed in a complementary metal-oxide-semiconductor (CMOS)-compatible technology, showing that reducing the width of the devices below a few hundreds of nanometers leads to higher charge sensitivity. Moreover, devices composed of several wires in parallel further increase the exposed surface per unit footprint area, thus maximizing the signal-to-noise ratio. This technology allows a sub milli-pH unit resolution with a sensor footprint of about 1 µm², exceeding the performance of previously reported studies on silicon nanowires by two orders of magnitude.
authors.affiliation: Institute of Bioengineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland. enrico.accastelli@epfl.ch.
authors.forename: Enrico
authors.initials: E
authors.lastname: Accastelli
authors.affiliation: DIEGM, Università degli Studi di Udine, 33100 Udine, Italy. scarbolo.paolo@spes.uniud.it.
authors.forename: Paolo
authors.initials: P
authors.lastname: Scarbolo
authors.affiliation: Laboratoire d'Électronique et de Technologie de l'Information (LETI), Commissariat à l'Énergie Atomique et aux Énergies Alternatives (CEA), 38054 Grenoble Cedex 9, France. thomas.ernst@cea.fr.
authors.forename: Thomas
authors.initials: T
authors.lastname: Ernst
authors.affiliation: DIEGM, Università degli Studi di Udine, 33100 Udine, Italy. palestri@uniud.it.
authors.forename: Pierpaolo
authors.initials: P
authors.lastname: Palestri
authors.affiliation: DIEGM, Università degli Studi di Udine, 33100 Udine, Italy. luca.selmi@uniud.it.
authors.forename: Luca
authors.initials: L
authors.lastname: Selmi
authors.affiliation: Institute of Bioengineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland. carlotta.guiducci@epfl.ch.
authors.forename: Carlotta
authors.initials: C
authors.lastname: Guiducci
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D006863:Hydrogen-Ion Concentration; D053770:Nanowires / Q000737:chemistry*; D059629:Signal-To-Noise Ratio; D012825:Silicon / Q000737:chemistry*; D014173:Transistors, Electronic
chemical_list: D012825:Silicon
keywords: 1/f noise; ISFET; pH sensors; silicon nanowires; tri-gate transistors