Performance and Reliability of Low-Temperature Processed SrBi[sub 2]Ta[sub 2]O[sub 9] Capacitors for FeRAM Applications

Abstract

Low-temperature processed (SBT) capacitors were tested as the ferroelectric memory cells of fully functional ferroelectric random access memory (FeRAM) devices. The 100 nm thick SBT films were deposited by the spin-on coating technique using a metallorganic decomposition source and crystallized by rapid thermal annealing at 700°C for 1 min followed by a furnace annealing at 650°C for 1 h under oxygen atmosphere, considered a low thermal budget process. The fabricated Pt/SBT/Pt capacitors showed reasonable ferroelectric performances with a (switching polarization-nonswitching polarization) of approximately 10 μC/cm2 after the full process integration. The FeRAM chip-level reliability analysis showed that the major reason for the function failure was from the opposite state retention characteristics due mainly to the small values. A 10-year guaranteed lifetime can be achieved when the operation voltage is higher than approximately 4 V at the test condition of 85°C operation and 125°C storage. © 2004 The Electrochemical Society. All rights reserved.