Semiconductor transistor (DMOS) device for use as a power amplifier

The invention relates to in particular a lateral DMOST with a drain extension. In the known transistor a further metal strip is positioned between the gate electrode contact strip and the drain contact which is electrically connected with the source region contact. In the device proposed here, the connection between the further metal strip and the source contact comprises a capacitor and the further metal strip is provided with a further contact region for delivering a voltage to the further metal strip. 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 is integrated with the transistor in a single semiconductor body. The invention further comprises a method of operating a device according to the invention.