DocumentCode :
1342307
Title :
The Random Telegraph Signal Behavior of Intermittently Stuck Bits in SDRAMs
Author :
Chugg, Andrew Michael ; Burnell, Andrew J. ; Duncan, Peter H. ; Parker, Sarah ; Ward, Jonathan J.
Author_Institution :
MBDA UK Ltd., Bristol, UK
Volume :
56
Issue :
6
fYear :
2009
Firstpage :
3057
Lastpage :
3064
Abstract :
This paper reports behavior analogous to the Random Telegraph Signal (RTS) seen in the leakage currents from radiation induced hot pixels in Charge Coupled Devices (CCDs), but in the context of stuck bits in Synchronous Dynamic Random Access Memories (SDRAMs). Our analysis suggests that pseudo-random sticking and unsticking of the SDRAM bits is due to thermally induced fluctuations in leakage current through displacement damage complexes in depletion regions that were created by high-energy neutron and proton interactions. It is shown that the number of observed stuck bits increases exponentially with temperature, due to the general increase in the leakage currents through the damage centers with temperature. Nevertheless, some stuck bits are seen to pseudo-randomly stick and unstick in the context of a continuously rising trend of temperature, thus demonstrating that their damage centers can exist in multiple widely spaced, discrete levels of leakage current, which is highly consistent with RTS. This implies that these intermittently stuck bits (ISBs) are a displacement damage phenomenon and are unrelated to microdose issues, which is confirmed by the observation that they also occur in unbiased irradiation. Finally, we note that observed variations in the periodicity of the sticking and unsticking behavior on several timescales is most readily explained by multiple leakage current pathways through displacement damage complexes spontaneously and independently opening and closing under the influence of thermal vibrations.
Keywords :
DRAM chips; charge-coupled devices; leakage currents; neutron effects; proton effects; telegraphy; SDRAM; charge coupled devices; damage centers; displacement damage phenomenon; high-energy neutron interactions; high-energy proton interactions; intermittently stuck bits; microdose issues; multiple leakage current pathways; pseudorandom sticking; radiation induced hot pixels; random telegraph signal behavior; synchronous dynamic random access memories; thermal vibrations; thermally induced fluctuations; Charge-coupled image sensors; Dark current; Fluctuations; Leakage current; Neutrons; Protons; Random access memory; SDRAM; Telegraphy; Temperature; Hard errors; neutrons; protons; single event effects;
fLanguage :
English
Journal_Title :
Nuclear Science, IEEE Transactions on
Publisher :
ieee
ISSN :
0018-9499
Type :
jour
DOI :
10.1109/TNS.2009.2032184
Filename :
5341348
Link To Document :
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