Muhammad Mustafa Salameh

University of North Carolina at Chapel Hill

Project Title: Part One
Part Two
Advisor: Prof. Eric Kvam

Introduction

In recent years, ferroelectric materials and thin films have attracted much attention and exhibited potential in many important applications such as dynamic random access memories (DRAMS), non-volatile ferroelectric random access memories micro-armours and infrared sensors. At present, the ferroelectric material, BaTiO3 (BT) is suitable for these systems, which are studied with a great deal of interest.

The remnant polarization (Pr) and coercive field (Ec) of these materials were determined to be 15 ?C/cm2 and 0.65kV/cm respectively, showing a satisfactory piezoelectric property. During this research the goal is to try to reproduce these results in showing that Barium Titanate is a good insulator.

Ferroelectric materials have several advantages such as an extremely low coercive field, a high remnant polarization, better mechanical strength and small deviation in composition, that could have a strong potential application for ferroelectric thin film devices.

Project Objectives

Show BaTiO is an insulator Adjust orientation and control strains Control growth Integrate with Joel Merrimans Project dealing with Strontium Ruthenate Reduce fatigue of polarization; Increase Lifetime

*After certain amounts of switching there has been degradation of performance and poor retention of stored information

Approach

Cutting and Cleaning Substrates
Make Sol-Gel (process of making the thin films) solution Spin Coating
Low Temp./ High Temp Annealing
Metallography, XRD, Optical Microscopy, SEM
Top electrode and Probe Station

Findings

Throughout this research, many difficulties were encountered and overcomed. After figuring out how to work the probe station to test the thin films developed, I was able to observe that Barium Titanate was an insulator. Showing that Barium Titanate was an insulator I got the oppurtunity to grow single crystal Barium Titanate on Magnesium Oxide single crystal thin films. Due to time contraints nearing the end of the program I did not get and chance to refine my single crystals or integrate my project with Joel Merriman's to show how a good ferroelectric thin film should work.

Overall, Barium Titanate showed to be a good insulator, was able to grow BaTio3 on silicon substrate and on MgO single crystals.


Figure 1. SEM picture of BaTi03 on silicon, shows growth of BaTiO3.
Figure 2. XRD Plot Showing Barium Tianate Growth on Silicon Substrate.

Contact me: salameh@email.unc.edu