Fabricating of a quantum device with autoalignment of the gates on their respective active zone region

A method for fabricating a quantum device, comprising:

• forming, on a semiconductor active zone resting on a substrate, a stack comprising a gate dielectric layer, at least one layer of gate material and one or more masking layers on the at least one layer of gate material,
• forming, above the semiconductor active zone, a trench by etching through the one or more masking layers, the trench extending in a first direction, the first direction being parallel to a plane of the substrate, the trench etching being stopped on the at least one layer of gate material,
• forming one or more masking elements traversing the trench, the one or more masking elements being transverse with respect to the trench and being separate from each other, the one or more masking elements extending in a second direction, the second direction being parallel to the plane of the substrate and being orthogonal to the first direction,
• anisotropically etching parts of the one or more masking layers not protected by the one or more masking elements, whereas regions of the one or more masking layers protected by the one or more masking elements remain unetched and form a masking block,
• removing the one or more masking elements,
• anisotropically etching the at least one layer of gate material so as to form a gate block vertically in line with each masking block, the gate block extending in the second direction, and
• etching the semiconductor active zone.

A method for fabricating a quantum device, the method comprising:

• forming, on an active zone of semiconductor material resting on a substrate, a stack comprising at least one layer of gate material and one or more masking layers on the at least one layer of gate material,
• forming, above the active zone, a trench by etching through the one or more masking layers, the trench extending in a first direction parallel to a plane of the substrate,
• forming, in the one or more masking layers of the stack, one or more pairs of masking blocks, each pair of masking blocks including a first masking block and a second masking block facing the first masking block, the first masking block and the second masking block being disposed facing each other and on either side of the trench, the first masking block and the second masking block extending in a second direction, the second direction being parallel to the plane of the substrate and being orthogonal to the first direction,
• etching the at least one layer of gate material so as to form a gate block vertically in line with each pair of masking blocks, the gate block extending in the second direction, and
• removing, at a bottom of the trench, at least a part of the active zone located vertically in line with one or more removed surface portions of the at least one layer of gate material,
• wherein the removing the bottom of the trench of the at least a part of the active zone comprises etching the active zone over an entire thickness thereof.