Leakage mechanism of local junctions forming the main or tail mode of retention characteristics for dynamic random access memories

We have reported the test structure for measuring the leakage characteristi cs of the local junctions. In this paper, we analyze the measurement result s of the leakage characteristics of local pn junctions. We determined that the trap-assisted tunneling mechanism controls the leakage current of the m ain mode cells. It is observed that the increment of the leakage current at the leaky junctions in the tail mode is smaller than that at the normal ju nctions in the main mode when the supply voltage is increased. We propose a two-traps related leakage mechanism for the leakage current of the pn junc tions in the rail mode. The two-traps pair increases the leakage current an d forms the tail mode in the distribution of retention time of the dynamic random access memories.