Nonvolatile memory disturbs due to gate and junction leakage currents

We address disturbs due to gate oxide and junction leakage currents in floating gate nonvolatile memories (NVM). The junction leakage is important, because the gate oxide current is proportional to junction current. We find the low gate leakage current to be caused by field ionization (FI) from traps within the gate oxides. Such low gate leakage currents can lead to sufficient charge accumulation to disturb charge in the floating gate. Through detailed simulations and measurements, we have determined the main cause of "write disturb" and "erase disturb" to be FI gate oxide current at low electric fields and Fowler-Nordheim current at high electric fields. Additional currents are due to high-energy electrons from the junction leakage current. (C) 2002 Elsevier Science Ltd. All rights reserved.