Low-temperature anodic oxidation of silicon using a wave resonance plasma source

A rf wave resonance plasma (WARP) source has been used to plasma oxidize Si at temperatures below 100 degrees C. Oxidation under positive substrate bi as in constant current mode gives an oxidation rate of 1-8 nm/min for curre nt densities of 0.4-5.5 mA/cm(2). This corresponds to an ionic (O-) current of about 10% of the total current, which is 2-5 times higher than previous ly reported, due to the high plasma density of 10(12)-10(13) cm(-3) achieve d by the WARP source. The breakdown field of similar to 10 MV/cm and the et ch rate of 60 nm/min of the oxide are independent of the oxidation rate and similar to those of the thermal oxide. Results from capacitance-voltage me asurements, Fourier transform infrared absorbance spectroscopy, null ellips ometry, and Rutherford backscattering spectroscopy suggest that the oxide g rown at low rates (< 2 nm/min) is very close to stoichiometric SiO2 while t he oxide grown at high rates (> 3 nm/min) is Si rich (35%-40% atomic Si). ( C) 1999 American Institute of Physics. [S0003-6951(99)02930-7].