Stacked indium gallium arsenide nanosheets on silicon with bottom trapezoid isolation

A method of forming a nanosheet semiconductor device comprising:

• forming a stack of at least two repeating nanosheets, the at least two repeating nanosheets including a first nanosheet layer of a first III-V semiconductor material and a second nanosheet layer of a second III-V semiconductor material;
• forming source and drain regions on the second nanosheet layer;
• removing a portion of the first nanosheet layer in the stack of the at least two repeating nanosheets selectively to the second nanosheet layer, wherein the etch process for removing the portion of the first nanosheet layer is selective to facets of the material for the first nanosheet to provide a inverted apex at the base of the stack;
• depositing a dielectric layer filling the inverted apex region;
• and
• forming a gate structure for the nanosheet semiconductor device to the channel region portion of the second nanosheet layer.

A nanosheet semiconductor device comprising:

• at least two repeating nanosheets, the at least two repeating nanosheets including a first nanosheet layer of a first III-V semiconductor material and a second nanosheet layer of a second III-V semiconductor material;
• a gate structure around a channel region of the at least two repeating nanosheets;
• and
• a trapezoid shaped dielectric material present underlying the gate structure, wherein the trapezoid shaped dielectric material is present between the gate structure and a III-V semiconductor material layer having a different composition than the two repeating nanosheets, wherein the trapezoid shaped dielectric material has an inverted apex at its base.