Alpha-particle-induced charge transfer between closely spaced memory cells

A detailed analysis of various mechanisms involved in α-particle-induced charge transfer between two trench-type DRAM cells is reported. An analytical model has been developed to describe the charge-transfer mechanisms. The charge-collection process consists of two phases. In the first phase, funneling is tile dominant mechanism, and the axial current is calculated based on the drift component. In the second phase, the structure behaves similarly to a bipolar transistor, and both the drift and diffusion components contribute to the charge transfer. A discussion of the dependence of the charge transfer on stored charge, cell separation, charge in the α-particle track, and the substrate doping concentration is presented.