A Novel Ion-Bombarded and Plasma-Passivated Charge Storage Layer for SONOS-Type Nonvolatile Memory

Abstract

A novel technique combination of ion bombardment (IB) and NH 3 plasma treatment (PT) has been presented to yield a highly effective charge storage layer for Si/SiO2/Si3N4/SiO2/Si (SONOS)-type nonvolatile memory applications. The IB technique creates additional trap sites within the charge storage layer strikingly to enhance the charge trapping/detrapping efficiency of the storage layer, and the NH 3 PT passivates shallow trap sites significantly to improve reliability characteristics. The distribution of trap sites corresponding with various energy levels is clearly described by discharge-based multipulse analysis. As compared with the control sample (without IB and NH 3 PT), the ionbombarded and NH 3 -plasma-passivated memory device has faster program/erase speeds and larger memory window. In addition, the competent reliability properties of the ion-bombarded and NH 3 -plasma-passivated memory, such as good endurance, long data retention, and acceptable disturbance, were also demonstrated in this letter.Index Terms-Discharge-based multipulse (DMP), Flash memory, ion bombardment (IB), metal/Al2O3/Si3N4/SiO2/Si (MANOS), NH 3 plasma treatment (PT).

High-Performance Multilevel-Storage Cu-Doped SiO_x-Based Nonvolatile Resistance Memory Using Ion Bombardment Technique

“…Recently, multi-level-cell (MLC) operation of resistance random access memory (ReRAM) has been actively investigated for next-generation high-capacity nonvolatile memory [1]. In all kinds of ReRAMs, Cu-doped SiO x -based (SiO x :Cu-based) ReRAM has attracted much attention since Cu and SiO x materials have been completely compatible with modern CMOS technology [2]. However, a conventional SiO x :Cu ReRAM generally has disappointing performance due to the use of infinite Cu source, thereby being completely incompetent to do MLC application [3,4].…”

A hot hole-programmed and low-temperature-formed SONOS flash memory

“…Compared to conventional floating-gate memory, SONOS-type memory has the advantage of high date retention, high endurance, and fast program/erase (P/E) speed [2]. However, the primary drawback of this memory type is that a higher voltage (typically >10 V) is required to inject carriers into the charge trapping layer, which results in excessive power consumption and leakage current.…”

Low temperature below 200 °C solution processed tunable flash memory device without tunneling and blocking layer

“…Today's semiconductor memory technology is dominated by silicon-oxide-nitride-oxide-silicon (SONOS) non-volatile flash memory which is based on intrinsic charge traps in silicon-rich silicon nitride films deposited by high temperature (∼ 780 o C) compatible chemical vapor deposition [19,20]. The intrinsic charge traps in silicon-rich silicon nitride films were first reported in 1967 [21] and the first flash memory device incorporating silicon nitride charge storage was demonstrated in 1980's [22].…”

“…However the trap density and distribution are difficult to control in such material [23]. Traps can be increased by ion bombardment and plasma-passivation [20], but the leakage current increases. Alternate high-k dielectrics such as TiO 2 , HfO 2 , ZrO 2 , etc.…”

“…From the sweep direc-tion of the CV curve it is inferred that gate injection of carriers controls the memory operation. Although conventional flash memory architecture follows channel injection of carriers [20], the interface degrades fast in such devices [34]. Thus, compared to channel injected devices, gate-injected devices show higher endurance which is one of the key requirements of memory operation [35].…”