An apparatus includes a semiconductor transistor structure. The semiconductor transistor structure includes dielectric material, a channel region, a gate, a source overlap region, and a drain overlap region. The source overlap region is biasable to cause a first voltage difference between the source overlap region and the gate to exceed a breakdown voltage of the dielectric material. The drain overlap region is biasable to cause a second voltage difference between the drain overlap region and the gate to exceed the breakdown voltage. The apparatus includes a well line coupled to a body of the semiconductor transistor. The apparatus includes circuitry configured to apply a voltage to the well line to prevent a breakdown condition between the channel region and the gate.