Optimization of a nanoribbon charge-based biosensor using gateless BESOI pMOSFET structure

Abstract

Nanoribbons built on gateless (GL) Ultra-Thin Body and Buried Oxide (UTBB) Back Enhanced SOI (BESOI) pMOSFET are analyzed as a charge-based (CB) biosensor for different sensing materials and device’s dimensions. Experimental GL UTBB BESOI pMOSFET are used as a reference structure for the CB biosensor and the influence of different materials and the device’s dimensions are studied by numerical simulations. CB biosensor presents higher sensitivities in weak inversion and for negative charges in the front gate oxide once that, for negative charges, the conduction at the front interface in BESOI pMOSFET is favored. An optimization is performed for negative charges and devices with thicker buried oxide (tBOX = 50 nm) and silicon channel (tSi = 20 nm) are more sensitive, improving the BESOI biosensor’s sensitivity in 14% in weak inversion. The improvement in strong inversion is higher (38%) but the absolute value is three times lower. The nanoribbon GL BESOI pMOSFET showed to be a promising structure for an integrated charged based biosensor, which can be easily fabricated in conjunction with the signal processing circuit.