Semiconductor fabrication with electrochemical apparatus

A method, comprising:

• forming a gate trench between two gate spacers over a semiconductor substrate, such that the gate trench exposes a portion of the semiconductor substrate;
• forming an interfacial layer in the gate trench between the gate spacers by supplying a positive bias to the semiconductor substrate to oxidize the exposed portion of the semiconductor substrate;
• and
• forming a gate structure over the interfacial layer to fill the gate trench.

A method, comprising:

• forming a source/drain region over a semiconductor substrate;
• depositing a metal layer over the source/drain region;
• annealing the semiconductor substrate to form a metal silicide layer by reacting the source/drain region with a portion of the metal layer;
• converting an unreacted portion of the metal layer into a metal oxide layer after annealing the semiconductor substrate by supplying a positive bias to the semiconductor substrate;
• and
• removing the metal oxide layer.