Process for controlling mobile ion contamination in semiconductor devices

DETAILED DESCRIPTION In the present invention the disadvantages of the phoso-silicate glass are avoided by forming a dielectric layer, typically silicon dioxide, by any desired means and then ion implanting therein a material capable of gettering the mobile ions.
In a preferred embodiment, the gettering agent includes phosphorus.
In another aspect of the invention, a mobile ion gettering agent is ion implanted into a layer of photoresist.
When the photoresist is ashed, the sodium impurities are neutralized by the gettering agent.
Furthermore, that portion of the implanted gettering agent which is not required to neutralize sodium atoms in the resist material will remain on or in the underlying layer and be available for neutralizing mobile ion contaminants which are produced by later steps in the processing of the wafer.