We observe electrically asymmetrical source‐drain characteristics in in‐plane‐gated transistors with shaped channels, and investigate them for different geometries. We give a qualitative explanation of the asymmetry, which is supported by voltage contrast scanning electron micrographs and the measured interaction between two neighboring channels. These shaped channels show a much higher dc voltage gain than conventional in‐plane‐gated transistors. ©1995 American Institute of Physics.