本文揭示的一种说明性方法包含其中移除未被闸极结构覆盖的整体鳍片结构的垂直高度部分的至少一部分，结果定义出位于所述闸极结构下方的所述整体鳍片结构的剩余部分，其中，所述剩余部分包括沟道部分以及位于所述沟道部分的较低部分。所述方法继续形成可热膨胀材料(HEM)层，于HEM上运行加热制程以使HEM膨胀，凹陷HEM以暴露沟道部分的边缘以及使用沟道部分的暴露边缘作为生长表面以于HEM的上方生长半导体材料。

One illustrative method disclosed herein includes, among other things, removing at least a portion of a vertical height of portions of an overall fin structure that are not covered by a gate structure so as to result in the definition of a remaining portion of the overall fin structure that is positioned under the gate structure, wherein the remaining portion comprises a channel portion and a lower portion located under the channel portion. The method continues with the formation of a layer of heat-expandable material (HEM), performing a heating process on the HEM so as to cause the HEM to expand, recessing the HEM so as to expose edges of the channel portion and growing a semiconductor material above the HEM using the exposed edges of the channel portion as a growth surface.