Design of a novel high-sensitive SOI-Junctionless BioFET overcoming sensitivity degradation problems.

For the first time, a new configuration of label-free junctionless semiconductor device is proposed to boost sensitivity in the identification of biomolecule specifies. Instead of creating the nanocavity inside the gate oxide, the nanocavity is created in the channel region which is very useful for the SOI junctionless technology based biodevice having a high current in all operating modes. For better control of the conduction mechanism, a hole trench is created under the channel region just inside the buried oxide. This will help to modulate the energy bands terminating in enhancing the sensing performance. Unlike the conventional biosensors needing a large-scale gate oxide thickness for trapping the biomolecules, the proposed biosensor can work for very low gate oxide thickness. The different biomolecules such as Biotin, Protein A, Bacteriophage T7, and Apomyoglobin have been utilized as targeted biomolecules for evaluating the sensitivity. Comparing the proposed biosensor with the conventional and other biosensors showed an enhanced sensing performance. Practical related issues during the process of sensing in terms of fill factor percentage, steric hindrance of biomolecules, and the charges of biomolecules have been focused in the recommended biodevice. All the results exhibited high superiority of performance of the suggested biodevice as compared to the conventional biosensor.

Label-free detection of DNA by a dielectric modulated armchair-graphene nanoribbon FET based biosensor in a dual-nanogap setup.

A Double-Gate Armchair-Graphene Nanoribbon FET is proposed to realize a high-sensitive and small-size biosensor in order to detect DNA without high-cost and time-consuming labeling process. Two nanogap cavities open inside the top and bottom gate oxides by the method of sacrificed layer etching. When the DNA biomolecule is introduced to the nanogap cavity, the hybridization event which is actually the formation of a double-strand of DNA will occur thus electrically modulating the GNR channel leading to a change in the drain current. The important report of this research is about attained high sensitivity of the proposed biosensor for a vast spectrum of the DNA biological samples. It is worth noting that a DNA sequence by 23 nucleotides extracted from Neisseria gonorrhoeae can be detected as a special case. An extensive numerical approach has been applied in order to characterize the proposed biosensor. The suggested biosensor has been evaluated by solving Schrödinger equation )SE( with Non-Equilibrium Green Function (NEGF) method in the mode-space coupled into Poisson solver in a self-consistent manner assuming ballistic limit. Two different expressions of sensitivity in terms of the threshold voltage and current have been defined giving a good metric for the sensitivity analysis. The results revealed a relative sensitivity of 1 mV/nm2 by a filled area by the DNA about 120 nm2 showing the excellent superiority for the proposed biosensor as compared to other counterparts. The effective area of the proposed biosensor obtains 240 nm2 which is very small in comparison with other reports highlighting high capability of the biosensor in the detection. It has been shown that the proposed biosensor can be implemented in ultra-scaling domain resulting in considerable increase in the sensitivity promising a potent and reliable candidate for high-sensitive and small-size biosensors. Also, the technical issues on designing the suggested biosensor have been investigated to achieve a useful guideline in detection and identification of the target DNAs.