| abstract |
The present invention relates to an isolation structure of a fin field effect transistor. An exemplary structure for the fin field effect transistor includes a substrate comprising a major surface; A plurality of fin structures protruding from the major surface of the substrate; And a plurality of isolation structures between the plurality of fin structures, each of the plurality of fin structures including an upper portion and a lower portion separated at a transition position, wherein the sidewalls of the fin structure at the transition position are formed on the substrate of the substrate. At an angle of 85 degrees with respect to the major surface, the upper portion having a sidewall substantially perpendicular to the upper surface with the major surface and the first width of the substrate, the lower portion being greater than the upper and the first width; With sidewalls inclined opposite the base with two widths, each of the plurality of separation structures extends from the major surface of the substrate to a point above the transition location. |