Impact of NF3-Added Interlayer Dielectric High Density Plasma Process on Hump Effect in Submicron n-type Metal Oxide Silicon Field Effect Transistor

The impact of high-density plasma (HDP) film over a bit line on the hump effect of n-type metal oxide silicon field effect transistor (nMOSFET) has been intensively investigated. In this work, it was found that the hump effect of nMOSFET is mainly due to hydrogen-induced positive charges produced by hydrogen diffusion into Si/SiO2. An interlayer dielectric (ILD)-HDP process with a low concentration of hydrogen suppresses the nMOSFET hump effect effectively compared to that with a high concentration of hydrogen. Additionally, it is noted that a NF3-added HDP process enables removal of hydrogen from the system owing to the strong interaction of fluorine with hydrogen, contributing to the suppression of the nMOSFET hump effect significantly without degradation of the characteristics of the gate oxide.