Effects of TiN Deposition on the Characteristics of W/TiN/SiO[sub 2]/Si Metal Oxide Semiconductor Capacitors

Abstract

We report the effects of the TiN deposition technique on the generation and annihilation of interface traps and oxide trapped charges in (2–6 nm)/Si metal oxide semiconductor (MOS) system during direct metal gate process. The TiN films were prepared by reactive sputtering using the Ti target or chemical vapor deposition (CVD) using and Sputter-deposited TiN not only generated a high level of interface traps from the bandedge to the near midgap of Si, but also introduced oxide trapped charges of The damages annealed out for (⩾3 nm) to the range of by the post-metal anneal (PMA) at 800°C in or at 450°C in forming gas. The interfacial damages for ultrathin (∼2 nm), however, were hardly capable of relieving even after the PMA of 800°C, resulting in an interface trap density in the high range. The level created after CVD-TiN was as low as with negligible even without PMA, and this level was further reduced to after PMA. We observed a noticeable increase of the capacitance equivalent thickness when prepared with CVD-TiN plausibly due to Cl from the source gas. © 2001 The Electrochemical Society. All rights reserved.