Impact of Heavy-Ion Strikes on Minimum-Size MOSFETs With Ultra-Thin Gate Oxide

Abstract

In this work we have investigated the effects of irradiation and electrical stress of nanocrystal memory cell arrays. Heavy ion irradiation has no or negligible immediate effects on the nanocrystal MOSFET characteristics, and on the programming window of the cells. By electrically stressing irradiated device, we see accelerated oxide breakdown similar to that previously observed on conventional thin gate oxide MOS capacitors, but no appreciable change of the degradation kinetics in terms of programming window closure and shift. The accelerated breakdown is ascribed to the degradation of the oxide-nitride-oxide (ONO) layer used as control oxide after exposure to ionising irradiation

Heavy-ion induced single event upsets in phase-change memories

“…The conclusions here are different from those in [12] (no upsets in 45 nm), due to the different architecture of the tested PCM cells -μtrench vs wall -which strongly impact the size of the region that needs to be amorphized to get an upset.…”

“…In [12], using a combination of published and reasonable values for a(0) 2 and g, the numbers shown in Fig. 9 were obtained.…”

“…trapped charge build-up and interface state generation in insulating layers struck by ionizing particles, are not expected to be a concern either. Microdose is known to give rise to stuck bits in SRAM cells [11] with relatively thick gate oxide, because of changes in the threshold voltage [12]. More recently, it has been reported that vertical power MOSFETs can display large leakage after single heavyion strike, due to the activation of parasitic current paths [13].…”

“…This is consistent with the absence of effects observed using neutrons having a terrestriallike wide energy spectrum. After [12].…”

Upsets in Phase Change Memories Due to High-LET Heavy Ions Impinging at an Angle

“…Microdose effects, observed for instance in low-voltage and Power MOSFETs [14][15], are not expected to be a concern either. In fact, phase change cells are known to withstand very high doses and sensitivity is not expected to grow with scaling.…”