A driver circuit for a three-dimensional (3D) memory device has a field management structure electrically coupled to a gate conductor. The field management structure causes an electric field peak in a vertical channel of the 3D memory device when a voltage differential exists between the source conductor and the drain conductor and the gate conductor is not biased. The electrical field peak can adjust the electrical response of the driver circuit, enabling the circuit to have a higher breakdown threshold voltage and improved drive current. Thus, the driver circuit can enable a scalable vertical string driver that is above the memory array instead of under the memory array circuitry.