Impact of silicidation on the excess noise behaviour of MOS transistors

The excess noise behaviour of silicided and non-silicided p- and n-channel MOSTs, biased in the ohmic region, has been investigated. Only a minor difference in noise and series resistance could be seen for the n-channel MOSTs. However, the noise in the non-silicided p-MOSTs was dominated by the noise in the series resistance. The series resistance for the non-silicided p-MOSTs was more than four times higher than for the silicided p-MOSTs. A modified model for the 1/f noise equivalent circuit is proposed, showing good agreement with experimental results and explaining the observed trend SId∝Idm with 0 < m < 4. The classical geometry dependence of the current noise in MOSTs is only valid if the noise in the series resistance is negligible.