This invention comprises a field effect transistor which comprises source and drain electrodes (01) which are bridged by a semiconductor which comprises semiconducting crystallites, the conductivity of the semiconductor being controlled by a gate electrode (02) which is insulated from the semiconductor and the source and drain electrodes, to which a potential is applied for controlling the conductivity of the semiconductor, in which at least part of the facing surfaces of the source and drain electrodes are geometrically formed such that they provide current flow of different directions between the electrodes through the said channel. By this means current is caused to flow through more orientations of the crystals resulting in greater uniformity of performance between different transistors when there is a degree of variable crystallographic orientation.