Mobile Charge in a Novel Spin-on Oxide (SOX): Detection of Hydrogen Dielectrics.

We studied the behavior of mobile charges, which we believe are hydrogen ions, in a novel spin-on oxide SOX. Our analysis is based on the Triangular Voltage Sweep (TVS) technique which is normally used to detect the presence of mobile alkali ions in silicon dioxides. We found that the TVS traces of protons exhibit several unique features which allow us to distinguish the proton signal from that of other common contaminants, such as Na. We suggest a model to explain these unique features. We show that the presence of hydrogen in the SOX material is due to high water retention ability of this porous oxide. Hydrogen in the intermediate dielectrics and encapsulation materials of MOS VLSI is known to be detrimental to MOS devices. It reacts with hot carriers and causes threshold instability and degradation of device characteristics. Our results are important for hydrogen detection in other materials that are potentially useful as intermediate dielectrics in multi-level metallization schemes.