A method for forming at least part of a quantum information processing device is presented. The method includes providing a first electrically-conductive layer formed of a first electrically-conductive material (100′) on a principal surface of a substrate (10), depositing a layer of dielectric material on the first electrically-conductive material, patterning the layer of dielectric material to form a pad of dielectric material and to reveal a first region of the first electrically-conductive layer, depositing a second electrically-conductive layer (104′) on the pad of dielectric material and on the first region of the first electrically-conductive layer, patterning the second electrically-conductive layer and removing the pad of dielectric material using isotropic gas phase etching.