Integrating bottom-up grown silicon nanowires on a CMOS chip to realize high-density transistor arrays for chemical sensing

Abstract

We report on a new sensor platform for chemical sensing featuring 1024 individually addressable field-effect transistors (FETs), based on small bundles of nominally undoped Si nanowires (SiNWs). The SiNW devices are integrated directly on top of control and readout circuits fabricated in complementary metal-oxide-semiconductor (CMOS) technology. The sensing mechanism is based on electrical field tuning of the conductivity through Schottky junctions at the metal/Si nanowire interfaces [1]. We show integration, electrical measurements and pH-sensing of a high-density array (≥100 devices/mm2) with a sensing area of 1 x 5μm2 per sensor element.