Thin silicon oxides grown by low-temperature rf plasma anodization and deposition

Abstract

We have studied the low-temperature (<500 °C) growth and deposition of thin silicon oxides in an rf plasma system. Oxides were grown by plasma anodization, sputter deposition, and combinations of these two processes. The oxides were electrically characterized with high-frequency and low-frequency capacitance-voltage techniques and the quality was found to depend strongly on plasma process parameters. In particular, we found strong dependences on bias current, plasma potential, and oxygen partial pressure. Under presently optimal conditions we have fabricated oxides with oxide charge densities Qox<1×1011 charges/cm2, interface state densities Dss<2×1011 states/cm2/eV, and breakdown fields Eb>13 MV/cm. Finally, we have studied the reduction of fast surface states in the plasma oxides by rapid thermal annealing.