Testing SBT Ferroelectric Thin Films for Non-Volatile RAM

Abstract

A combined method for testing a sol-gel derived strontium bismuth tantalate (SBT) film for non-volatile ferroelectric RAM memories (NVFERAM) that combine fatigue and retention measurements is compared with the conventional one. It results more alike to how a memory cell works in a RAM. Differences between both methods are described and results are discussed on the base of a pining/depining process of domains. A complementary measurement method which based on a programmable logic device has been developed that provides digital responses, to test a ferroelectric capacitor as a single storage cell in a manner close to how a RAM works in a computer, following the measuring strategy of the combined method. Voltage signals are used to write and read information in a small capacitor used as memory cell, evaluating the film before its insertion into the integrated device.

Keywords:

• Ferroelectric films
• SBT
• RAM
• measurement method

ACKNOWLEDGMENTS

This work was funded through the Comision Interministerial de Ciencia y Tecnologia (CICYT) of Spain under Project MAT98-1068.

Notes

τ_R= τ_W = 5 μ s and V_R = V_W = 5 V are the pulses width and amplitude, R/W = read/write.