1. A contact structure in an integrated circuit, comprising: a semiconductor substrate having a first patterned metal interconnect layer, wherein the first patterned metal interconnect layer forms an interconnect; a first insulating layer overlying the first patterned metal interconnect layer; an opening through the first insulating layer to the first patterned metal interconnect layer; a first titanium nitride layer overlying portions of the first insulating layer and extending into the opening to contact the first patterned metal interconnect layer exposed through the opening; an amorphous silicon layer overlying the first titanium nitride layer; a second titanium nitride layer overlying the amorphous silicon layer; insulating sidewalls surrounding the first titanium nitride layer, amorphous silicon layer, and second titanium nitride layer; and a second patterned metal interconnect layer overlying the first insulating layer, the insulating sidewalls, and the second titanium nitride layer, and in contact with the second titanium nitride layer.