Atomic absorption spectroscopic measurements of silicon atom concentrations in electron cyclotron resonance silicon oxide deposition plasmas

The silicon atom densities in both silane/oxygen and tetraethoxysilane (TEOS)/oxygen electron cyclotron resonance (ECR) plasmas were measured as functions of microwave power, pressure, and gas flow rates. An atomic absorption spectrometer with a Si hollow-cathode lamp was constructed for these measurements. Silicon atom densities in silane/oxygen ECR discharges increase with rising plasma density, and a strong correlation was found between the Si atom gas-phase abundance and the silicon oxide film deposition rate. The measured Si concentrations [(1-7) x 10(10) cm(-3)] were high enough to account for a significant part of the film growth in the silane based chemistry. In TEOS/O-2 discharges Si atom concentrations were lower by an order of magnitude, so Si is probably not a major contributor to the growth rate in that case. The internal temperature of Si atoms was found to vary from 380 to 720 K with increasing microwave power (200-650 W). (C) 1999 American Institute of Physics. [S0021-8979(98)03823-7].