ELECTRICAL CHARACTERIZATION OF MOS MEMORY DEVICES WITH SELF-ASSEMBLED TUNGSTEN NANO-DOTS DISPERSED IN SILICON NITRIDE

摘要

Crystallized W-NDs dispersed in silicon nitride were prepared by self-assembled nanodot deposition (SAND) with extremely high density (1.3x1013/cm2) and small size (1~1.5nm), successfully. XPS results show that the high metallic states of tungsten are remained after 800℃ anneal due to the surround silicon nitride. MOS memory capacitor with W-NDs floating gate and HfO2 blocking dielectric was fabricated. A hysteresis memory window of～1.0V is observed under low sweeping gate voltage of ±5V. A maximum memory window as large as 29V was obtained with sweeping gate voltage of ±23V, suggesting that it is a good candidate for multi-bit nonvolatile memory application.