ELECTRON-CYCLOTRON-RESONANCE PLASMA SOURCE FOR METALORGANIC CHEMICAL-VAPOR-DEPOSITION OF SILICON-OXIDE FILMS

An electron cyclotron resonance (ECR) plasma source was employed for low-temperature (50-300-degrees-C) metalorganic plasma-enhanced chemical vapor deposition of silicon oxide films. The plasma was excited in mixtures of oxygen and tetraethylorthosilicate vapor, and oxygen and tris(trimethylsiloxy)boron (TTMSB) vapor. The operation pressure range was 1-50 mTorr; oxygen and metalorganic vapor flow rates varied from 10 to 100 sccm. Microwave power (f =2.45 GHz, P = 100-1500 W) was introduced into a 15-cm-diam ECR chamber via a microwave quartz introduction window. A static magnetic field in the plasma chamber was generated by two Helmholtz coils. It had intensity near the microwave window, B(vw) = 875-935 G in a narrow plasma mode, and B(vw) = 1000-1100 G in a uniform plasma mode. Silicon dioxide films were deposited onto a 10-cm-diam silicon wafer located at 16 cm from the source output. A line-averaged plasma density N(e)BAR was measured with a microwave interferometer (35 MHz) at 11 cm from the source output. In the mixture of TTMSB vapor and oxygen (20 mTorr), N(e)BAR was 1.5-1.7 X 10(11) cm3 and then decreased as pressure grew. The film deposition rate increased with TTMSB flow rate; it had a maximum value of 1200 angstrom/min at total pressure of 15-20 mTorr.