Hemispherical $p/n/p$ transistor structures ranging from 100 μm down to 0.05 μm in diameter are fabricated in ${\mathrm{CuInSe}}_2,$ by application of a high electric field between a conducting diamond tip of an atomic force microscope and a ${\mathrm{CuInSe}}_2$ crystal. This leads to electromigration of Cu ions in the bulk of the material. The results of this thermally assisted process are the transistor structures. These are characterized by scanning spreading resistance microscopy. For large devices these results are compared and found to agree with those of “conventional” electron-beam-induced current ones. Removing several tens of atomic layers from the top surface of a structure does not affect the spreading resistance image of the device. This indicates the three-dimensional hemispherical nature of the structures.

• Received 6 August 1998

DOI:https://doi.org/10.1103/PhysRevB.59.10877