Fabrication and characterization of metal-ferroelectric-semiconductor non-volatile memory using BaTiO_3 film prepared through sol-gel process

摘要

In the present work, a metal-ferroelectric-semiconductor (MFS) structure for non-volatile memory application using barium titanate (BaTiO3) thin film is proposed. Sol-gel method is used to prepare the material, while deposition is done through spin-coating. A thin layer of BaTiO3 (BTO) film on a silicon substrate with MFS structure is fabricated followed by N-2 dominant gas annealing. The electrical properties and the non-volatile memory operations characteristics of prepared MFS structure with BTO as the ferroelectric thin film are observed and discussed. Two different solvents are used to prepare the sol-gel of BTO material and prepared films are compared on the basis of morphological and electrical properties. It is found that the film prepared by 2-methoxyethol is better than the film prepared by ethanol. The device's performance is evaluated by changing the annealing temperature and variable sweep voltages. Memory window and leakage current improve at higher annealing temperature with saturation at 650 degrees C. A maximum of 6 V memory window is achieved for 650 degrees C annealed device. Saturation in memory window is also observed with respect to the voltage sweep up to - 6 V to + 6 V with a considerable remnant polarization value. Endurance property for the MFS structure shows promising result for the iteration cycle of 10(13) using positive up negative down pulse testing. To the best of author's knowledge, this is the first report on BTO based MFS structure for memory application prepared through sol-gel process.