METAL-SEMICONDUCTOR HETEROSTRUCTURES IN 3D FOR ELECTRON STORAGE AND VERTICAL INJECTION

Applications of a GaAs-layer, which has artificially been made semi-in sulating by overlapping depletion regions from a matrix of buried meta l discs, are considered. A study of capacitance transients is used to investigate electron capture into the nano-Schottky contacts during a voltage pulse. The dependence of the capture process on temperature, p ulse bias and filling time has been measured, revealing a Coulomb repu lsion of subsequent electrons as they are captured into the discs. The time constant for the emission of the captured electrons has been stu died for different temperatures, and the storage time of excess electr ons on the discs is found to depend strongly on the temperature. Furth ermore, a vertical, sub-micrometer-sized, conducting channel is create d in deliberately vacant disc positions in the buried disc lattice. Th e effective area of the channel is demonstrated to vary with the volta ge at 4.2 K. We attribute this effect to a field-induced lowering of t he barrier at the edges of the channel. (C) 1998 Elsevier Science Ltd. All rights reserved.