In-Plane Gate Transistors With a 40- $\mu\hbox{m}$ -Wide Channel Width

An in-plane gate transistor with a GaAs/AlGaAs 2-D electron-gas channel about 40 μm in width is investigated. The saturation region and the drain current modulation at different gate bias voltages are observed despite the wide channel. The surface-induced channel depletion is suggested as the main mechanism for the turn-off of the drain current at - 10 V gate bias.