Synthesis of Cobalt-Based Nanocrystal Layer in Silicon Dioxide for Nonvolatile Memory Applications

초록

Cobalt suicide (CoSi) nanocrystal (NC) layer distributed within narrow spatial region is synthesized by thermal annealing of a sandwich structure comprised of a thin cobalt (Co) film sandwiched between two silicon-rich oxide (SiO(x)) layers. It is shown that the size of the Co Si NCs can be controlled by varying the Co film thickness, an increase in the size with increasing thickness. Capacitance voltage (C-V) measurements on a test metal/oxide/semiconductor (MOS) structure with floating gate based on Co Si NCs of 3.8 nm in diameter and 1.4 x 10(12) cm(2) in density are shown to have C-V characteristics suitable for nonvolatile memory applications, including a C V memory window of about 9.5 V for sweep voltages between -15 V and +8, a retention time >10(8) s, and an endurance >10(6) program/erase cycles.

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