supersensitive field/charge sensor
V.A. Krupenin, D.E. Presnov, V.S. Vlasenko, S.V. Amitonov
Recently, silicon nanowire devices have received considerable attention as regards use in integrated nanoscale electronics as well as for studying fundamental properties in small dimensions. Besides this, the nanowires are in the point of view as the basis for the highly sensitive chemical and biological sensors, and they are also very attractive objects for the application in the field of emission devices, photonics and spintronics.
In this work we used the traditional microelectronics techniques for the preparation of the field-effect transistor based on silicon nanowire since they are strongly simplify the fabrication process. The design features of device are connected with Schottky's barriers formed in the regions of the electrode metal contacts (Ti) with source and drain of transistor. The experimental samples were prepared from the silicon-on-insulator (SOI) material using the methods of electron-beam lithography and reactive-ion etching, forming the structure in the top silicon layer. The bulk silicon substrate was used as a gate for the transistor.
Voltage-current characteristics of the experimental structures over a wide range (-10V - +10V) of the gate voltages were measured. The most attention were paid for the positive charge of the gate, since in this case the inverse (electron) conductance channel of the transistor is used. All the structures, like the traditional semiconductor transistors, demonstrate the saturation of current with an increase source - drain voltage. The transistor current depends from the gate voltage, in mean of the electric filed, inducted by this gate.
This effect give as the possibility to register the small charged particles, attached to the nanowire. In this aspect the device become very attractive for the biological applications as a biosensor for detecting of ultralow concentrations and even single particles of the proteins, viruses and DNA. Initially were used the single – grown nanowires, but now the SOI material makes it possible to use the integral technology for the sensor fabrication.
In conclusion, we demonstrate the simple fabrication technology for the silicon nanowire field-effect transistor, which can be used as a supersensitive field/charge sensor for the biological applications.
Fabrication method for the silicon nanowire field-effect transistor from silicon-on-insulator (SOI) material was demonstrated. The process of the transistor formation was simplified and didn't use the stages of doping and subsequent activation. The design features of device are connected with Schottky's barriers formed in the regions of the electrode metal contacts (Ti) with source and drain of transistor. Voltage-current characteristics of the experimental structures over a wide range (10 V +10 V)of the gate voltages were measured. The possibility of using of the silicon nanowire field-effect transistor as a supersensitive field/charge sensor was analyzed