A method for forming a transistor structure comprising a fin-shaped channel structure

摘要

A method for forming a transistor structure comprising a fin-shaped channel structure, comprising:
- providing a layer stack embedded laterally in STI structures;
- recessing the STI structures adjacent to the layer stack to thereby expose an upper portion of the layer stack, the upper portion comprising at least a channel portion;
- providing one or more protection layers on the upper portion of the layer stack;
- after providing one or more protection layers, further recessing the STI structures selectively to the protection layers and the layer stack, to thereby expose a central portion of the layer stack;
- removing the central portion of the layer stack, resulting in a freestanding upper part and a lower part of the layer stack being physically separated from each other;
wherein providing the layer stack comprises providing an etch stop layer at a position directly below the channel portion, such that the freestanding upper part of the layer stack comprises an etch stop layer at its lower surface after selectively removing the central portion.