MOS transistor and a method of manufacturing an MOS transistor

The MOS transistor (1) of the invention comprises a gate electrode (10), a channel region (4), a drain contact region (6) and a drain extension region (7) mutually connecting the channel region (4) and the drain contact region (6). The MOS transistor (1) further comprises a shield layer (11) which extends over the drain extension region (7) wherein the distance between the shield layer (11) and the drain extension region (7) increases in a direction from the gate electrode (10) towards the drain contact region (6). In this way the lateral breakdown voltage of the MOS transistor (1) is increased to a level at which the MOS transistor (1) may fulfill the ruggedness requirement for broadcast applications for a supply voltage higher than that used in base station applications.