Time dependent breakdown of ultrathin gate oxide

Time dependent dielectric breakdown (TDDB) of ultrathin gate oxide (4.8 MV/cm. The TDDB activation energy for this type of gate oxide was found to have linear dependence on oxide field. In addition, we found that /spl gamma/ (the field acceleration parameter) decreases with increasing temperature. Furthermore, it was found that testing at high temperatures (up to 342/spl deg/C) and low electric field values did not introduce new gate oxide failure mechanism. It is also shown that TDDB data obtained at very high temperature (342/spl deg/C) and low fields can be used to generate TDDB model at lower temperatures and low fields. Our results (an enthalpy of activation of 1.98 eV and dipole moment of 12.3 e/spl Aring/) are in complete agreement with previous results by McPherson and Mogul. Additionally, it was found that TDDB is exponentially dependent on the gate voltage.