Method of making multiple nano layer transistors to enhance a multiple stack CFET performance
A semiconductor device is provided. The semiconductor device has a first transistor pair formed over a substrate. The first transistor pair includes a n-type transistor and a p-type transistor that are stacked over one another. The n-type transistor has a first channel region that includes one or more first nano-channels with a first stress. The one or more first nano-channels extend laterally along the substrate, are stacked over the substrate and spaced apart from one another. The p-type transistor has a second channel region that includes one or more second nano-channels with a second stress. The one or more second nano-channels extend laterally along the substrate, are stacked over the substrate and spaced apart from one another. Each of the one or more first nano-channels in the first channel region and each of the one or more second nano-channels in the second channel region are surrounded by a gate structure respectively.
1. A semiconductor device, comprising:
a first transistor pair formed over a substrate, the first transistor pair including a n-type transistor and a p-type transistor that are stacked over one another, the n-type transistor having a first channel region that includes one or more first nano-channels with a first stress, the one or more first nano-channels extending laterally along the substrate, being stacked over the substrate and spaced apart from one another, the p-type transistor having a second channel region that includes one or more second nano-channels with a second stress, the one or more second nano-channels extending laterally along the substrate, being stacked over the substrate and spaced apart from one another, each of the one or more first nano-channels in the first channel region and each of the one or more second nano-channels in the second channel region being surrounded by a gate structure respectively;
a second transistor pair formed over the substrate, the second transistor pair including a n-type transistor and a p-type transistor, the second transistor pair being positioned at a first side of the first transistor pair, a n-channel region of the n-type transistor of the second transistor pair being coupled to a first source/drain (S/D) region of the n-type transistor of the first transistor pair, a p-channel region of the p-type transistor of the second transistor pair being coupled to a first S/D region of the p-type transistor of the first transistor pair; and
a third transistor pair formed over the substrate, the third transistor pair including a n-type transistor and a p-type transistor, the third transistor pair being positioned at a second side of the first transistor pair, a n-channel region of the n-type transistor of the third transistor pair being coupled to a second S/D region of the n-type transistor of the first transistor pair, a p-type channel region of the p-type transistor of the third transistor pair being coupled to a second S/D region of the p-type transistor of the first transistor pair.
2. The device of claim 1 , wherein the first stress comprises a tensile stress and the second stress comprises a compressive stress.
3. The device of claim 1 , wherein the one or more first nano-channels are made of silicon carbon (SiC).
4. The device of claim 3 , wherein the SiC has a carbon content between 2% and 20%.
5. The device of claim 1 , wherein the one or more second nano-channels are made of silicon germanium (SiGe) with a germanium content between 5% and 30%.
6. The device of claim 1 , wherein the one or more first nano-channels comprises a number N of nano-channels, the N being an integer from one to ten.
7. The device of claim 1 , wherein the one or more second nano-channels comprises a number M of nano-channels, the M being an integer from one to ten.
8. The device of claim 1 , wherein:
the first S/D region and the second S/D region of the n-type transistor are made of silicon doped with phosphorous, the first S/D region and the second S/D region of the n-type transistor being positioned at two ends of the one or more first nano-channels and in direct contact with the one or more first nano-channels; and
the first S/D region and the second S/D region of the p-type transistor are made of silicon doped with boron, the first S/D region and the second S/D region of the p-type transistor being positioned at two ends of the one or more second nano-channels and in direct contact with the one or more second nano-channels.