A switching transistor includes a substrate having a substrate dopant concentration and a barrier region bordering on the substrate, having a first conductivity type and having a barrier region dopant concentration that is higher than the substrate dopant concentration. A source region is embedded in the barrier region, and has a second conductivity type and has a dopant concentration that is higher than the barrier region dopant concentration. A drain region is embedded in the barrier region and is offset from the source region. The draining region has the second conductivity type and a dopant concentration that is higher than the barrier region dopant concentration. A channel region extends between the source region and the drain region, wherein the channel region comprises a subregion of the barrier region. An insulation region covers the channel region and is disposed between the channel region and a gate electrode. The barrier region dopant concentration and the substrate dopant concentration are chosen for generating a space-charge region around the source region and the drain region and for depleting the barrier region.