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

We present the first evidence of single event upsets in 45-nm phase change memories caused by high linear energy transfer (LET) heavy ions at tilted angles along the word line. Angular and LET dependences are presented, together with a discussion of the possible underlying mechanisms. The occurrence of a thermal spike, due to the ion passage, close to the heater/storage element interface is identified as the most plausible explanation. The upset cross section is compared with that of NOR Flash and finally the impact of scaling on the sensitivity of future memories is analyzed.