Field-effect transistor

摘要

A field-effect transistor (5) has a plurality of cells having nodes (81) and branches (82). For example, each of the cells has a central node in the form of a circular portion of a base region (54), three branches in the form of rectangular portions of the base region and extending radially outwardly from the central node and angularly spaced at an angle of 120 DEG , and circular portions of the base region which are connected to distal ends of the rectangular portions of the base region. The cells are uniformly arranged in an active region (73) of a drain layer (12). The field-effect transistor has a small on-resistance because the base region of each cell has a large peripheral length, has a smaller gate-to-drain capacitance than with polygonal cells, and has a high withstand voltage because the base region has no corners.