Semiconductor device comprising a field-effect transistor and method of operating the same

The invention relates to in particular a lateral DMOST with a drain extension (8). In the known transistor a further metal strip (20) is positioned between the gate electrode contact strip and the drain contact (16) which is electrically connected with the source region contact (15). In the device proposed here, the connection between the further metal strip (20) and the source contact (15,12) comprises a capacitor (30) and the further metal strip (20) is provided with a further contact region (35) for delivering a voltage to the further metal strip (20). In this way an improved linearity is possible and the usefulness of the device is improved in particular at high power and at high frequencies. Preferably the capacitor (30) is integrated with the transistor in a single semiconductor body (1). The invention further comprises a method of operating a device (10) according to the invention.