Nanostructural and Electrical Properties of Al/Sn/La2O3 Nanocomposite as a Gate Dielectric of MOSFETs

Abstract

Metal–oxide–semiconductor field-effect transistors (MOSFETs) have significant role on producing the electronic devices. The producers try to make the chips in smaller size so they need materials with high dielectric constant. Here, in this research, Al/Sn/La2O3 will introduce as a material with higher dielectric constant and less defections. In this research, Al/Sn/La2O3 nanostructure was prepared by sol–gel and spin-coating methods. Lanthanum chloride (LaCl3·7H2O), cetyltrimethylammonium bromide, ammonia (25%), aluminum tri-sec-butylate (C12H27AlO3), acetyl acetone (C2H5O8), isopropyl alcohol (C3H8O), Tin (II) chloride (SnCl2) and H2O were used to synthesize Al/Sn/La2O3. Structural properties and surface morphology of nanocrystallites were investigated by X-ray diffraction, differential scanning calorimetry, scanning electron microscopy, atomic force microscopy and Fourier-transform infrared radiation, respectively. Electrical properties were determined with metal–dielectric–semiconductor through capacitance–voltage (C–V), the hysteresis curve and current density–voltage (J–V). The conduction mechanism was measured in the temperature range of 330 K < T < 410 K and in the electrical field < 0.12 MV cm−1, and the results showed ohmic emission. A thermal excited model was proposed to explain the mechanism of ohmic conduction current. The highest value of dielectric constant (k) for Al/Sn/La2O3 structure was 33 at T = 250 °C with almost amorphous structure. The result showed that $$ \frac{{I_{\text{on}} }}{{I_{\text{off}} }} $$ of Al/Sn/La2O3 structure was ~ 1.3. The leakage current and capacitance–voltage of Al/Sn/La2O3 nanocomposite for the sample calcined at T = 250 °C showed that this sample can be good enough for using as a gate dielectric of MOSFETs.