Self-aligned gate isolation for multi-directional gate layouts in quantum and semiconductor devices

A method for fabricating a self-aligned gate structure with multiple metallic gate electrodes, comprising:

• forming at least one first trench having a first width in a gate structure comprising a first metallic gate layer of metallic gate electrodes;
• forming at least one second trench having a second width in the gate structure, wherein the first width is smaller than the second width;
• depositing at least one conformal dielectric layer on the first metallic gate layer, wherein the at least one conformal dielectric layer completely fills the at least one first trench, and the at least one conformal dielectric layer partially fills the at least one second trench, such that a portion of the at least one second trench is unfilled;
• depositing a conformal second metallic gate layer of metallic gate electrodes on the at least one conformal dielectric layer, wherein the conformal second metallic gate layer fills up the unfilled portion of the at least one second trench;
• and
• removing one or more portions of the conformal second metallic gate layer to expose the at least one conformal dielectric layer;
• wherein one or more remaining portions of the conformal second metallic gate layer include self-aligned metallic gate electrodes.