VELOCITY MODULATION IN FOCUSED-ION-BEAM WRITTEN IN-PLANE-GATE TRANSISTORS

The mobility of a one-dimensional electron gas can be changed markedly by moving the electron path from the high-mobility channel toward the low-mobility focused ion-beam-implanted regions. This can be done sim ply by applying different biases to the two adjacent in-plane gates. W hen the bias voltage on one gate is fixed, we increase the other gate potential and force the current path close to the ion-implanted region . In this way the mobility rather than the density of the carriers is controlled, which is the key feature of the velocity modulation transi stors with inherently fast response.