Parasitic leakage in DRAM trench storage capacitor vertical gated diodes

Extensive characterization and mechanism modeling have been done on a newly observed parasitic voltage dependent junction leakage current which is inherent in the gated diodes of DRAM trench storage nodes. Excellentagreement is shown between model and data. Comparison of the observed voltage and temperature dependence to the model indicates that, in the normal range of operation, this current is limited by the diffusion of thermally generated carriers along the gated node surface. The design and reliability implications are discussed.