Abstract: A method of fabricating two terminal mesa semiconductor devices comprising etching a surface doped and metal coated silicon slice thereby to form a plurality of silicon frusta each capped by a metal contact pad, covering the frusta side of the slice with a metal contact continuity layer and then with a handle layer formed to lie parallel with that surface of the silicon slice which is remote from the frusta, lapping away the silicon slice to expose parts of the handle layer which extend between the frusta so that the frusta are separated so as to define discrete mesas held together by the handle layer, forming one of the two terminals on a face of the mesas remote from the contact pads, removing the handle layer to reveal the contact pads and bonding each contact pad thereby revealed to the metallized face of a diamond heat sink, one heat sink to each contact pad, which heat sink forms a part of the other of the two terminals of each mesa semiconductor device.