Thirty-Day-Long Data Retention in Ferroelectric-Gate Field-Effect Transistors with HfO2 Buffer Layers
- 1 August 2005
- journal article
- Published by IOP Publishing in Japanese Journal of Applied Physics
- Vol. 44 (8R) , 6218
- https://doi.org/10.1143/jjap.44.6218
Abstract
Metal–ferroelectric–insulator–semiconductor (MFIS) diodes and p-channel MFIS field-effect transistors (FETs) were fabricated and their electrical properties were characterized. These MFIS structures were formed using HfO2 as an insulating buffer layer, and SrBi2Ta2O9 (SBT) and (Bi,La)4Ti3O12 (BLT) as ferroelectric films. HfO2 buffer layers of about 8 nm physical thickness were deposited by ultrahigh-vacuum (UHV) electron-beam evaporation, then ferroelectric films of about 400 nm thickness were deposited by sol–gel spin coating. The fabricated p-channel MFIS-FETs with the SBT/HfO2 gate structure exhibited a drain current on/off ratio larger than 103 even after 30 days had elapsed. It was also found that the degradation of ferroelectricity was not pronounced even after applying 2.2×1011 bipolar pulses.Keywords
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