DLTS Measurements of Thin-Oxide MOS Capacitors

Silicon metal-oxide-semiconductor field-effect transistors (MOS FETs) are one of the fundamental building blocks of modern electronics. The most critical component is the oxide-semiconductor interface in the MOS stack. In an effort to determine if these devices are suitable for quantum information applications, we have performed deep-level transient spectroscopy (DLTS) measurements on Silicon MOS capacitors with a thin thermal oxide (~10 nm) layer from room temperature down to ~30 K. The measurements were performed on samples of various metals with and without forming gas anneals. We observed that samples that were annealed show very few features in the transient spectrum, while unannealed samples show features consistent with defects in the silicon. Further, we observed interesting dynamic in the long-term behavior of the device capacitance following a transient. We will discuss the method that we used to make the measurements, present the results, and provide conjectures about the observed behavior.