Statistical evaluation for anomalous SILC of tunnel oxide using integrated array TEG

We propose a new test-element-group (TEG) in order to study anomalous stress-induced leakage current (SILC) of tunnel oxide, which is a problem for flash memory reliability. Using this TEG, gate current through the tunnel oxide in the order of 10^-16 A can be measured for about 1,000,000 transistors within 4 minutes. The behavior of anomalous SILC when Fowler-Nordheim (FN) electron tunneling stress is applied or measurement temperature is changed was investigated. It was detected that the anomalous SILC appears or disappears by applying stress and it was annealed out at high temperature measurement, as observed in flash memory cells. This TEG can be fabricated by simple processes, and its peripheral circuits are simple structures, so the tunnel dielectric can be changed drastically. We consider that using this TEG for the development of tunnel dielectric can lead to clarifying the origin of anomalous SILC, and promote the downscaling of tunnel dielectric thickness.