A method of making a semiconductor switch device. The method includes providing a semiconductor substrate having a major surface and a first semiconductor region having a first conductivity type located adjacent the major surface. The method also includes depositing a gate dielectric on the major surface. The method further includes implanting ions into the first semiconductor region through a mask positioned over the first semiconductor region, thereby to form a well region located in the first semiconductor region. The well region has a second conductivity type different to the first conductivity type. The method also includes depositing and patterning a gate electrode material on the gate dielectric to form a gate electrode located directly above the well region. The method further includes implanting ions into the first semiconductor region to form a source region and a drain region of the semiconductor switch device on either side of the gate electrode.