Interposers and methods of making the same are disclosed herein. In one embodiment, an interposer includes a region having first and second oppositely facing surfaces and a plurality of pores, each pore extending in a first direction from the first surface towards the second surface, wherein alumina extends along a wall of each pore; a plurality of electrically conductive connection elements extending in the first direction, consisting essentially of aluminum and being electrically isolated from one another by at least the alumina; a first conductive path provided at the first surface for connection with a first component external to the interposer; and a second conductive path provided at the second surface for connection with a second component external to the interposer, wherein the first and second conductive paths are electrically connected through at least some of the connection elements.