Experimental characterization of α-induced charge collection mechanism for megabit DRAM cells

Introduction The α -particle induced soft errors(l) in DRAM´s have become a major problem in reducing memory cell sizes. Intensive efforts have been made for studying charge collection mechanisms. diffusion(2) and funnellng(81. However. it is not clear yet how these mechanisms contribute to the critical charge Q_c of various cell sizes quantitatively. In this paper. a simple model for estimating Q_c Is proposed for memory cells with and without p_* barriers. based on experimental results using one-bit DRAM cells as well as a 3-D device simiulatorC4). In addition. a new mechanism. charge multiplication by weak avalanche, is found in memory cells with p_* barriers, and the influence of this mechanism on Q_c is also discussed.