The effect of fluorine on gate dielectric properties

MOS capacitors with fluorine implants have been fabricated to study the effect of fluorine on SiO2gate dielectric performance. Control capacitors with Ne implants have also been included to determine the effect of the ion implantation damage. Capacitance measurements indicate that low Ditand Nfare obtained in all cases. Ramped voltage measurements show no significant change in breakdown voltage with F and Ne dose. Constant current stress tests show larger injected charge values at breakdown with increasing implant dose. The change in fiat-band voltage with injected charge indicates additional hole traps as the F and Ne doses increase. In all cases, the results of F implantation are similar to those of Ne implantation, indicating that physical damage following implantation is dominant and the chemical effects of fluorine are negligible.