THE EFFECT OF OXYGEN ADDITION ON REACTIVE-ION-ETCHED SILICON DAMAGE IN CHF3 PLASMAS

The effect of adding oxygen to CHF3 plasmas on RIE silicon damage is studied. Measurements on metal oxide semi-conductor capacitors indicate that a decrease in carrier generation lifetime and an increase in surface recombination velocity has been observed with increasing oxygen percentage. Secondary ion mass spectroscopy depth profiling shows that a significant increase in carbon and fluorine can be seen on the etched silicon surface. These data demonstrate an increase in silicon damage with increasing F/C ratio and are consistent with previous data on CHF3 vs. CF4.