Electronics Weekly Electronics Design & Components Tech News
Building upon traditional FinFET principles, this innovation introduces an additional well in the nanowire that further enhances the sensitivity of the device.
The device features a 35-40nm wide silicon FinFET with a 25nm nanowell as the active sensing area.
Within the well, binding of an estimated ten short single-stranded DNA molecules boasts a clear signal of 40mV, which is the double of the signal achieved from the previous FinFET device.
Noteworthy are also its near-ideal electrical properties, marked by a subthreshold swing of 66 mV/dec, close to the theoretical minimum of 60. This demonstrates that electrolyte gating effectively happened inside the nanowell.
The challenges of creating such a nanowell FET lay in the need to remove material while preserving the integrity of the entire semiconductor device.
Imec‘s innovative processing techniques, such as sacrificial layers to enable the formation of the self-aligned nanowell, and precise material selection, including a C3N3 self-assembled monolayer coating, contribute to the device’s reproducibility, reliability, and pioneering design.
Transfer characteristic: Ids-Vgs curves for different Vds from 1 V to 0.1 V, illustrating the near-ideal electric properties of the device.
(a) Longitudinal and (b) cross-section TEM image of nwFET, showing important device structural parameters, including 2 narrow Si channels of 3-4 nm, the nanowell size of around 25 nm.
Overview of complete 20T ssDNA sensing experiment. (a), (b) and (c), indicate 3 different real-time tests: only during test 2 DNA is injected (b); (a) and (c) are reference tests. (d). The variation of the constant current voltage V0 during the experiment with the V0 shift between the red and blue markers indicating the end-point signal (≈ 40 mV).
Future steps involve experimental verification of single-molecule detection potential, for both the current nanowell and the earlier developed FinFET biosensor, and exploration beyond DNA sensing.
Imec also aims to explore nanopore FETs, enabling DNA sequencing and proteomics.
Combined, these innovations showcase the burgeoning potential of transistors in parallel biosensing at the nanoscale.
