A semiconductor switch device for switching an RF signal and a method of making the same. The device includes a first semiconductor region having a first conductivity type. The device also includes a source region and a drain region located in the first semiconductor region. The source region and the drain region have a second conductivity type. The second conductivity type is different to the first conductivity type. The device further includes a gate separating the source region from the drain region. The device also includes at least one sinker region having the second conductivity type. Each sinker region is connectable to an external potential for drawing minority carriers away from the source and drain regions to reduce a leakage current at junctions between the source and drain regions and the first semiconductor region.