Trench confined epitaxially grown device layer(s)
View Patent ↗Trench-confined selective epitaxial growth process in which epitaxial growth of a semiconductor device layer proceeds within the confines of a trench. In embodiments, a trench is fabricated to include a pristine, planar semiconductor seeding surface disposed at the bottom of the trench. Semiconductor regions around the seeding surface may be recessed relative to the seeding surface with Isolation dielectric disposed there on to surround the semiconductor seeding layer and form the trench. In embodiments to form the trench, a sacrificial hardmask fin may be covered in dielectric which is then planarized to expose the hardmask fin, which is then removed to expose the seeding surface. A semiconductor device layer is formed from the seeding surface through selective heteroepitaxy. In embodiments, non-planar devices are formed from the semiconductor device layer by recessing a top surface of the isolation dielectric. In embodiments, non-planar devices CMOS devices having high carrier mobility may be made from the semiconductor device layer.
1. A non-planar field effect transistor (FET) disposed over a silicon substrate, the non-planar FET comprising:
a source region and a drain region with a non-silicon semiconductor channel disposed there between and over a planar semiconductor seeding surface having a composition other than that of the non-silicon semiconductor channel, the planar semiconductor seeding surface being a top surface of a semiconductor mesa on the silicon substrate and surrounded by isolation dielectric wherein the semiconductor mesa is a different semiconductor than the silicon substrate and wherein the non-silicon semiconductor channel is a III-V binary, ternary or quaternary compound semiconductor alloy;
a gate dielectric layer and a gate electrode layer disposed over the non-silicon semiconductor channel.
2. The non-planar FET of claim 1 , wherein a center the channel is aligned with a center of the planar semiconductor seeding surface.
3. The non-planar FET of claim 2 , wherein a bottom surface of the isolation dielectric is in contact with a semiconductor surface recessed below the seeding surface.
4. The non-planar FET of claim 3 , wherein the seeding surface is recessed below a top surface of the dielectric isolation.
5. The non-planar FET of claim 3 , wherein the non-silicon semiconductor channel is one layer of a semiconductor stack having a top surface disposed a distance from the seeding surface at least three times a minimum lateral dimension of the seeding surface.