New α-Particle Induced Soft Error Mechanism in a Three Dimensional Capacitor Cell

Yukihito OOWAKI  Keiji MABUCHI  Shigeyoshi WATANABE  Kazunori OHUCHI  Jun'ichi MATSUNAGA  Fujio MASUOKA  

IEICE TRANSACTIONS on Electronics   Vol.E78-C   No.7   pp.845-851
Publication Date: 1995/07/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on LSI Memory Device, Circuit, Architecture and Application Technologies for Multimedia Age)
α-particle,  soft error,  DRAM,  

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This paper describes the new α-particle induced soft error mechanism, the Minority Carrier Outflow (MCO) effect, which may seriously affect the reliability of the scaled DRAMs with three dimensional capacitors. The MCO chargge increases as the device size miniaturizes because of the three dimensional capacitor effect as below. As the device scales down, the storage node volume decreases which results in the higher minority carrier density in the storage node and larger outflow charge. Also as the device plan view miniaturizes, the stack capacitor height or trench depth does not scales down or even increases to keep the storage node capacitance, therefore the initially generated minority carrier becomes larger. A simple analytical MCO model is introduced to evaluate the MCO effect quantitatively. The model agrees well with the three dimensional device simulation. The MCO model predicts that the life time of the minority carrier in the storage node strongly affects the MCO charge, however, even when the life time is as small as the order of 100 ps, the MCO effect can be the major soft error mechanism.