Low-Temperature Growth of Si Oxide with Good Electrical Qualities Using Helicon-Wave-Excited O2-Ar Plasma and Forming Gas Annealing.

P-type Si(100) substrate was oxidized using helicon-wave-excited O2–Ar plasma at low temperatures. Post–thermal annealings were performed after oxidation in forming gases (FGs) containing 3% and 5% H2. The capacitance–voltage (C–V) characteristics were significantly improved by post-thermal annealing at 500°C in FG containing 3% H2, and a minimum interface state density of 1.5 ×1010 eV-1cm-2 was obtained, which was comparable to those at device-grade thermal-Si–oxide/Si interfaces. The interface-state densities was about ~1011 eV-1cm-2 for the oxide samples post-thermally annealed in O2 ambient. The Fowler–Nordheim (FN) tunneling current is the dominant leakage current mechanism similar to that of thermal Si oxide. However, the barrier height was somewhat smaller than that of the thermal oxide. FN current stress experiments were carried out to simulate the hot-carrier injection endurance of the grown oxide film with both electrical polarities of the stress voltages. The shift of the threshold voltage was the smallest for the oxide sample post-thermally annealed in FG containing 3% H2. The results of the FN stressing could be well interpreted by the surface plasmon and avalanche breakdown models.