Dependence on Gate Voltage Low-Level

5.5.1 Dependence on Gate Voltage Low-Level

To compare stress and relaxation properly, the initial charge pumping signal $it Icp,0$ should stay constant over the whole considered low level gate voltage $VG$ -region. Hence, under the assumption that only interface states contribute, $Icp$ should actually become independent of $VG,low$ as soon as the strong inversion regime is reached. This $Icp,0it$ is marked by the dashed line in Fig. 5.13. However, as demonstrated previously [44, 43], $Icp$ continues to increase, albeit at a much slower rate. This increase with $ΔVG$ is routinely attributed to slower oxide traps $ΔNot$ and $Icp = I it + I ot cp cp$ [47, 97]. So, regardless of the amount of degradation, $I cp$ varies as function of $V G,low$ . This fact has to be taken into account for a meaningful comparison of stress and relaxation CP data.

[next] [front] [up]