DEGRADATION OF FLASH MEMORY USING DRAIN-AVALANCHE HOT-ELECTRON (DAHE)SELF-CONVERGENCE OPERATION SCHEME

In this paper, the n-channel Flash memory device degradation by utiliz ing the drain-avalanche hot electron (DAHE) self-convergence (S-C) sch eme is demonstrated for the first time. The injected hole originated b y the channel electron induced avalanche hot hole generation is believ ed to be responsible for this degradation. This hole injection phenome na not only result in the interface state generation but also lead to the hole trapping in the tunnel oxide. The increased interface states degrade the conduction of the channel current severely, which leads to abnormal write/erase (WIE) endurance characteristics. The trapped hol es in the tunnel oxide increase the tunneling probability and cause th e gate disturbance issue. From the concerns of long term reliability, the self-convergence operation by utilizing the DAHE mechanism is not a proper scheme for reliable Flash memory products.