The thickness effect of insulator layer between the semiconductor and metal contact on C-V characteristics of Al/Si3N4/p-Si device

Abstract

Metal-insulator-semiconductor (MIS) structures have great interest for their good applications in electronic and optoelectronic. Their importance can be attributed that they have storage layer property, capacitance effect and high dielectric constant. For this reason, two samples of Si3N4 layers were deposited with plasma-enhanced chemical vapor deposition (PECVD) technique on p-type Si; first is about 5 nm thickness and the other is about 50 nm. The thicknesses of Si(3)N4 were adjusted by an ellipsometer. The thickness effect of Si3N4 layers on the Al/Si3N4/p type Si contact was studied with the capacitance-voltage (C-V) and conductance-voltage (G-V) characteristics of the contact at the frequency range from 10 kHz to 1 MHz and applied bias voltage from-5 V to +5 Vat room temperature. In each contact having different insulator layers, capacitance values decreased and conductance values increased with increasing frequencies. The interface states (Nss), the effect of series resistance (Rs), barrier height (1b) and carrier concentration (k) were found from the capacitance-voltage (C-V) and conductance-voltage (G-V) measurements and explained in the details. To determine memristor behavior of the Al/Si3N4/p type Si contact, dual C-V and G-V measurements were performed at 500 kHz and the room temperature, and the results were compared for 5 nm and 50 nm thicknesses layers. Consequently, changing of Si3N4 layer thickness influenced properties of the contacts, and these two contacts have memristor behavior and, they can be used and improved as memory devices in the future.