Abstract: A channel layer of n-type GaAs doped with Si as an impurity is formed on a GaAs semiinsulating substrate. A gate electrode of, for example, aluminum is formed on the channel layer. The gate electrode is in Schottky-contact with channel layer. Formed on opposite sides of the gate electrode on the channel layer are drain- and source side electric field relaxation layers of n-type In.sub.x G.sub.1-x As doped with impurities. Each electric field relaxation layer substantially produces a potential difference at its lateral edge portion by an electric current flowing across the lateral edge portion. A WSi drain electrode is formed on the drain-side electric field relaxation layer. A WSi source electrode is formed on the source-side electric field relaxation layer.

Abstract: An image search control apparatus provides an index number to a reproducer having a storage medium on which a plurality of still images constituting a motion picture is stored. Each still image is identified by an index number. The reproducer reproduces and provides as a video signal the plurality of still images constituting the motion picture and the index number of each still image. Alternatively, in response to receiving an index number, the reproducer reproduces and provides as the video signal the still image corresponding to the received index number. The image search control appartus comprises a selector that receives the video signal from the reproducer and that selects from the still images constituting the motion picture a number of selected still images. An index memory stores each of the selected still images and its index number. A display receives the video signal from the reproducer and also receives a number of selected still images from the index memory.