Transistor comprising an air gap positioned adjacent a gate electrode

A device, comprising:

• a gate electrode positioned above a semiconductor material region;
• a sidewall spacer positioned adjacent the gate electrode;
• a gate insulation layer having a first substantially horizontally oriented portion positioned between the gate electrode and the semiconductor material region and a second substantially vertically oriented portion positioned between a lower portion of the sidewall spacer and a sidewall of a lower portion of the gate electrode;
• an air gap cavity located between the sidewall spacer and an upper portion of the gate electrode, wherein an upper surface of the second substantially vertically oriented portion of the gate insulation layer and an upper surface of the lower portion of the gate electrode define an outer lateral boundary of the air gap cavity;
• and
• a gate cap layer positioned above the gate electrode, wherein the gate cap layer seals an upper end of the air gap cavity so as to define an air gap positioned adjacent the gate electrode,
• wherein the lower portion of the gate electrode has a lateral thickness that is greater than a lateral thickness of the upper portion of the gate electrode, and
• wherein the air gap cavity is in contact with the upper portion of the gate electrode.

A device, comprising:

• a gate electrode positioned above a semiconductor material region;
• a sidewall spacer positioned adjacent the gate electrode, the sidewall spacer comprising an inner surface and a vertical height;
• a gate insulation layer having a first substantially horizontally oriented portion positioned between the gate electrode and the semiconductor material region and a second substantially vertically oriented portion positioned along a portion of the vertical height of the sidewall spacer, wherein the second substantially vertically oriented portion of the gate insulation layer is positioned on and in contact with a lower portion of the inner surface of the sidewall spacer and on and in contact with a sidewall of a lower portion of the gate electrode;
• an air gap cavity located between the sidewall spacer and an upper portion of the gate electrode, wherein an upper surface of the second substantially vertically oriented portion of the gate insulation layer and an upper surface of the lower portion of the gate electrode define an outer lateral boundary of the air gap cavity;
• and
• a gate cap layer positioned above the gate electrode, wherein the gate cap layer seals an upper end of the air gap cavity so as to define an air gap positioned adjacent the gate electrode,
• wherein the lower portion of the gate electrode has a lateral thickness that is greater than a lateral thickness of the upper portion of the gate electrode, and
• wherein the air gap cavity is in contact with the upper portion of the gate electrode.