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Nonvolatile Flash Memory Device Using Ge Nanocrystals Embedded in HfAlO High-<tex>$kappa$</tex>Tunneling and Control Oxides: Device Fabrication and Electrical Performance

2004; Institute of Electrical and Electronics Engineers; Volume: 51; Issue: 11 Linguagem: Inglês

10.1109/ted.2004.837011

1557-9646

Jianhui Chen, Y.Q. Wang, Won Jong Yoo, Yee‐Chia Yeo, Ganesh Samudra, D.S.H. Chan, An Du, Dim‐Lee Kwong,

Electronic and Structural Properties of Oxides

We fabricated a nonvolatile Flash memory device using Ge nanocrystals (NCs) floating-gate (FG)-embedded in HfAlO high-/spl kappa/ tunneling/control oxides. Process compatibility and memory operation of the device were investigated. Results show that Ge-NC have good thermal stability in the HfAlO matrix as indicated by the negative Gibbs free energy changes for both reactions of GeO/sub 2/+Hf/spl rarr/HfO/sub 2/+Ge and 3GeO/sub 2/+4Al/spl rarr/2Al/sub 2/O/sub 3/+3Ge. This stability implies that the fabricated structure can be compatible with the standard CMOS process with the ability to sustain source-drain activation anneal temperatures. Compared with Si-NC embedded in HfO/sub 2/, Ge-NC embedded in HfAlO can provide more electron traps, thereby enlarging the memory window. It is also shown that this structure can achieve a low programming voltage of 6-7 V for fast programming, a long charge retention time of ten years maintaining a 0.7-V memory window, and good endurance characteristics of up to 10/sup 6/ rewrite cycles. This paper shows that the Ge-NC embedded in HfAlO is a promising candidate for further scaling of FG Flash memory devices.