Application of micro-Raman spectroscopy for the monitoring of quality of high-k (h-k) dielectric protective layer deposition onto the surface of a nanowire (NW) chip has been demonstrated. A NW chip based on silicon-on-insulator (SOI) structures, protected with a layer of high-k dielectric ((h-k)-SOI-NW chip), has been employed for highly sensitive detection of microRNA (miRNA) associated with oncological diseases. The protective dielectric included a 2-nm-thick Al₂O₃ surface layer and a 8-nm-thick HfO₂ layer, deposited onto a silicon SOI-NW chip. Such a chip had increased time stability upon operation in solution, as compared with an unprotected SOI-NW chip with native oxide. The (h-k)-SOI-NW biosensor has been employed for the detection of DNA oligonucleotide (oDNA), which is a synthetic analogue of miRNA-21 associated with oncological diseases. To provide biospecificity of the detection, the surface of (h-k)-SOI-NW chip was modified with oligonucleotide probe molecules (oDVA probes) complementary to the sequence of the target biomolecule. Concentration sensitivity of the (h-k)-SOI-NW biosensor at the level of DL~10⁻¹⁶ M has been demonstrated.

The linear charge coupling effect of threshold voltages V _th of the bottom (field) gate, i.e., a substrate of the silicon-on-insulator structure of fully depleted n-MIC transistors on a lightly doped silicon layer 20–50 nm thick, is studied depending on the voltage V _bg of the top asymmetrically biased (with negative polarity) N ⁺-poly-Si gate. It is shown that the quantum-mechanical correction conditioned by the electrostatically induced size effect of the transverse field should be considered when determining the linear charge coupling region between gates even at a silicon layer thickness of ∼50 nm. An increase in the positive charge on the surface states at the heterointerface with a silicon layer increases the quantum-mechanical correction by a factor of 2–4 due to the quantum capacitance effect affecting donor-trap recharging in the case of a significant difference between the opposite-polarity potentials of the two gates.

Results of numerical 2D and 3D-simulations of the performance of nanowire sensors on the basis of silicon-on-insulator structures aimed at determining the optimum conditions for the response to dielectric particles, are given. The effect of screening of nanowires by dielectric particles in solutions with pH = 7 used as a medium for transporting biological objects is considered.