US 12,068,415 B2
Precise bottom junction formation for vertical transport field effect transistor with highly doped epitaxial source/drain, sharp junction gradient, and/or reduced parasitic capacitance
Kai Zhao, Albany, NY (US); Shahab Siddiqui, Clifton Park, NY (US); Daniel James Dechene, Watervliet, NY (US); Rishikesh Krishnan, Cohoes, NY (US); and Charlotte DeWan Adams, Schenectady, NY (US)
Assigned to International Business Machines Corporation, Armonk, NY (US)
Filed by International Business Machines Corporation, Armonk, NY (US)
Filed on Oct. 15, 2022, as Appl. No. 17/966,817.
Application 17/966,817 is a division of application No. 16/901,852, filed on Jun. 15, 2020, granted, now 11,515,427.
Prior Publication US 2023/0029561 A1, Feb. 2, 2023
Int. Cl. H01L 29/78 (2006.01); H01L 21/8234 (2006.01); H01L 29/08 (2006.01); H01L 29/423 (2006.01); H01L 29/66 (2006.01); H01L 29/786 (2006.01)
CPC H01L 29/78642 (2013.01) [H01L 21/823418 (2013.01); H01L 29/0847 (2013.01); H01L 29/42392 (2013.01); H01L 29/66666 (2013.01); H01L 29/66795 (2013.01); H01L 29/785 (2013.01)] 11 Claims
OG exemplary drawing
 
1. A structure comprising:
a substrate having a plurality of first lower source-drain regions and a plurality of second lower source-drain regions, the plurality of first lower source-drain regions being doped with one of an n-type dopant and a p-type dopant, the plurality of second lower source-drain regions being doped with an opposite one of the n-type dopant and the p-type dopant, the plurality of first lower source-drain regions and the plurality of second lower source-drain regions having coplanar outer surfaces, the plurality of second lower source-drain regions being integral with the substrate, the plurality of first lower source-drain regions being epitaxially grown material in cavities of the substrate;
wherein the plurality of first lower source-drain regions has a plurality of first bottom junctions integral with, and extending from, the outer surfaces of the plurality of first lower source-drain regions, the plurality of first bottom junctions being doped with the one of the n-type dopant and the p-type dopant;
wherein the plurality of second lower source-drain regions has a plurality of second bottom junctions extending from the outer surfaces of the plurality of second lower source-drain regions, the plurality of second bottom junctions being doped with the opposite one of the n-type dopant and the p-type dopant;
a plurality of first fins located on the plurality of first bottom junctions, the plurality of first fins having outer ends;
a plurality of second fins located on the plurality of second bottom junctions, and cooperatively with the plurality of first fins, defining intermediate cavities, the plurality of second fins having outer ends, the intermediate cavities extending into the plurality of first lower source-drain regions and the plurality of second lower source-drain regions;
a plurality of spacer-gate structures located in the intermediate cavities;
a plurality of first top junctions located on the outer ends of the plurality of first fins;
a plurality of second top junctions located on the outer ends of the plurality of second fins;
a plurality of first upper source-drain regions located outwardly of the plurality of spacer-gate structures in contact with the plurality of first top junctions, the plurality of first upper source-drain regions being doped with the one of the n-type dopant and the p-type dopant; and
a plurality of second upper source-drain regions located outwardly of the plurality of spacer-gate structures in contact with the plurality of second top junctions, the plurality of second upper source-drain regions being doped with the opposite one of the n-type dopant and the p-type dopant.