Retention in metal–oxide–semiconductor structures with two embedded self-aligned Ge-nanocrystal layers

Abstract

Structural and electrical characterization has been carried out on metal-oxide-semiconductor (MOS) structures with a silicon dioxide (SiO 2 ) layer containing a germanium nanocrystals (Ge-ncs) floating gate. Ge-nc layers were embedded in SiO 2 by ion implantation with subsequent annealing. Structural analysis proved the presence of two self-aligned nanocrystal layers within the SiO 2 host material. The electrical results indicate a strong memory effect due to the presence of a near-interface Ge-nc layer. Few volts memory windows can easily be obtained at relatively low programming voltages (<6 V). For comparison, operating voltages used in current FLASH technology are about 12 V. Despite its promising structural properties, retention times extracted from capacitance measurements and scanning Kelvin microscopy were found to be too low (∼10 5 s) to comply with the non-volatility industry requirements (<10 years required).

Charge Storage in Pentacene/Polymethylmethacrylate Memory Devices

“…The top electrode forms the control gate, below which the "floating" nanoparticle gate is capacitively coupled to the gate and the underlying semiconductor. Charge storage effects may be conveniently studied using a metal-insulatorsemiconductor (MIS) structure.Various storage media have been investigated, including aluminum nanocrystals [1], germanium nanocrystals [2], gold nanocrystals [3], and Au nanoparticles [4]- [7]. Charging of nanomaterials occurs on the application of a voltage to the gate by charge transport, either directly from the semiconductor surface [6], [8] or via the top insulator [9].…”

Dielectric engineering of Ge nanocrystal/SiO2 nanocomposite thin films with Ge ion implantation: Modeling and measurement

“…One of the promising applications of the nc-Ge/SiO 2 nanocomposite thin films is the next-generation nonvolatile memory (NVM) devices owing to the extended scalability and improved memory performance, such as low operating voltages, fast program/erase speeds, good endurance and long data retention time [1][2][3][4]. In a typical NVM device, nc-Ge/SiO 2 thin films serve as the gate oxide of a field-effect transistor.…”

Gold nanoparticles as a floating gate in Pentacene/PVP based MIS memory devices

“…Memory devices play a massive role in all emerging technologies, as such, efforts to fabricate new organic memories to be utilized in flexible electronics is essential [4]. Nanofloating gate metal insulator-semiconductor (MIS) memory devices have been reported using Au, Ag, and Ge nanoparticles or C 6 0 nanocomposites as charge storage elements [6,8]. In our previous work we have reported on hybrid organic inorganic silicon-based MIS memories utilizing different storage media (gold nanoparticles-AuNPs, carbon nanotubes, C60 nanocomposite) and organic insulators to encapsulate the floating gate [9].…”