Electrodeposition of conformal electrodes for obtaining a tunnel junction with a vacuum nanogap

Abstract

Electrodeposition of a copper electrode on a Si substrate is performed to obtain a large-area vacuum nanogap for thermotunneling devices. To obtain the correct geometry of such an electrode and reduce internal stress in it, cathode rotation, various protective masks, asymmetric current mode, and electrolyte temperature control and stabilization were used. Reducing the electrode diameter to 3 mm and increasing the thickness of the initial silicon plate to 2 mm makes it possible to grow an electrode with a bend of about 2.5 nm/mm. This made it possible to obtain two conformal electrodes with a nanogap of less than 5 nm on an area of 7 mm². Such conformal electrodes can be used in devices based on electron tunneling.