What is more conductive, copper or doped silicon?
Doped silicon has various conductivities; some wafers [with 60 volt well_substrate sustaining voltage] are about 50 ohm_cm (that is, measured face to face across a 1cm cube, expect 50 ohms). Other materials may be 10 or 100X more conductive.
But copper? A 1cm by 1cm square of PCB copper foil (35 microns thick) is only 0.000500 ohms (that is 500 microOhms) from edge to edge.
If you thicken that foil by 10,000 micron (1cm) / 35 micron, or 280 more layers of PCB foil, your edge-edge measurement will be about 0.000002 ohms (yes --- that is 2 micro Ohms).
Thus the copper is about 1 Million times more conductive than doped silicon.