A silicon nanocrystals based memory

Abstract

A new memory structure using threshold shifting from charge stored in nanocrystals of silicon (≊5nm in size) is described. The devices utilize direct tunneling and storage of electrons in the nanocrystals. The limited size and capacitance of the nanocrystals limit the numbers of stored electrons. Coulomb blockade effects may be important in these structures but are not necessary for their operation. The threshold shifts of 0.2–0.4 V with read and write times less than 100’s of a nanosecond at operating voltages below 2.5 V have been obtained experimentally. The retention times are measured in days and weeks, and the structures have been operated in an excess of 109 cycles without degradation in performance. This nanomemory exhibits characteristics necessary for high density and low power.

Electronic transport of molecular systems

“…Electronic memories that operate at the charge limit (e.g., by single electron effects) have been demonstrated [34,35], but have not yet addressed the dimensional limit; i.e., a single molecule. Although memory phenomena has been studied in bulk organic materials (such as organometallic charge-transfer complex salts [1]), we will demonstrate nanoscale electronically programmable and erasable memory devices utilizing molecular SAM; and a memory cell applicable to a random access memory (RAM).…”

Classification and control of the origin of photoluminescence from Si nanocrystals

“…Besides their potential as light sources 12,13 , it has been shown that Si nanocrystals are strong candidates for a new generation of Flash memory that can be fabricated with minimal disruption to conventional silicon technology 14 .…”

The energy band alignment of Si nanocrystals in SiO2

“…Si nanocrystals (ncs) embedded in oxide host have been intensively studied both to investigate the properties of the matter at nanometric scale and for nanoelectronic, optoelectronic, and photovoltaic applications. [1][2][3][4] The band gap of Si ncs increases when their size shrinks. Several theoretical works described this issue 5 and different optical techniques as photoluminescence (PL), spectroscopic ellissometry, and optical absorption have been used to prove this fact.…”