Quantum dot devices

A method of operating a quantum dot device, comprising:

• applying a voltage to a first gate disposed on a fin to cause a first quantum dot to form in a first quantum well in the fin under the first gate, wherein the fin extends away from a base and an insulating material is disposed on side faces of the fin;
• applying a voltage to a second gate disposed on the fin to cause a second quantum dot to form in a second quantum well in the fin under the second gate;
• and
• applying a voltage to a third gate disposed on the fin to (1) cause a third quantum dot to form in a third quantum well in the fin under the third gate or (2) provide a potential barrier between the first quantum well and the second quantum well;
• wherein the first gate and the third gate are spaced apart along the fin by a first spacer, and the third gate and the second gate are spaced apart along the fin by a second spacer.

A method of manufacturing a quantum dot device, comprising:

• providing a quantum well stack on a substrate, wherein the quantum well stack includes a quantum well layer;
• removing at least some of the quantum well stack to form fins, wherein the fins include the quantum well layer;
• providing an insulating material between the fins;
• forming first and second gates on top of the fins;
• providing spacers on sides of the first and second gates, wherein a first spacer is disposed on a side of the first gate closest to the second gate, and a second spacer is disposed on a side of the second gate closest to the first gate;
• and
• forming a third gate on the fin, extending between the first and second spacers.

A quantum computing device, comprising:

• a quantum processing device, wherein the quantum processing device includes a first fin in parallel with a second fin, an insulating material disposed between the first fin and the second fin, an active quantum well layer in the first fin, a read quantum well layer in the second fin, first gates to control formation of quantum dots in the active quantum well layer, and second gates to control formation of quantum dots in the read quantum well layer;
• a non-quantum processing device, coupled to the quantum processing device, to control voltages applied to gates on the first and second fins;
• and
• a memory device to store data generated by the read quantum well layer during operation of the quantum processing device;
• wherein the first gates include at least three adjacent gates disposed on the first fin, wherein the three adjacent gates on the first fin are spaced apart by spacers;
• and
• wherein the second gates include at least three adjacent gates disposed on the second fin, wherein the three adjacent gates on the second fin are spaced apart by spacers.