The nanofabrication techniques which are used to create quantum dot diodes will be discussed. The device is a vertical resonant tunneling diode where the lateral dimensions are reduced to ∼1000 Å. Electron beam lithography is used to pattern a small self-aligned metal dot top contact and etch mask. The semiconductor dot is a cylinder ∼1000 Å in diameter and on the order of 100 Å thick, with the vertical potential defined by the double-barrier heterostructure and the lateral defined by the Fermi-level pinning of the free surfaces. Discrete energy states due to the three-dimensional confinement are observed and are spin degenerate only. Transport measurements through such a device will be presented.