Solid state sensor for metal ion detection and trapping in solution

An apparatus for in-situ detection of metal ion contamination in a solution, comprising:

• a vessel containing a solution;
• a semiconductor device formed on a substrate and disposed in said solution, said semiconductor device comprising at least one N-type material layer oriented in a first direction and covering a P-type material layer oriented in said first direction, and a dielectric layer disposed over said at least one N-type material layer and including an opening therethrough such that at least one contact part of said at least one N-type material layer directly contacts said solution;
• an illumination source arranged such that said semiconductor device is exposed to said illumination source;
• and
• electrical circuitry coupled to a structure of said semiconductor device and capable of testing at least one of conductance and resistance of said structure.

A method for removing metal ions from a solution comprising:

• providing a semiconductor device contacting a solution, said semiconductor device comprising a plurality of N-type material discrete portions of an N-type material layer that covers a P-type material layer, said N-type material discrete portions separated by dielectric plugs that extend through said N-type material layer and contact said P-type material layer, each said N-type material discrete portion having a contact that directly contacts said solution, adjacent ones of said contacts separated by said dielectric plugs;
• optically illuminating said semiconductor device thereby creating a voltage across a P/N junction and causing metal ions of said solution to become trapped at said contacts;
• and
• monitoring conductance of a structure of said semiconductor device having a conductance that varies with an amount of said metal ions trapped at said at least one contact part,
• said solution comprising an effluent stream from a semiconductor processing operation.