Methods for doping a sub-fin region of a semiconductor fin structure and devices containing the same

A semiconductor fin structure to be used in a semiconductor device, comprising:

• a plurality of fins disposed on a substrate wherein individual fins of the plurality of fins are laterally separated from other fins of the plurality of fins, and individual fins of the plurality of fins extend away from the substrate,
• wherein individual fins of the plurality of fins include a doped sub-fin region that is disposed on the substrate and an undoped top-fin region disposed on the sub-fin region, wherein a concentration of dopant material in the doped sub-fin region is greater proximate to a surface of the doped sub-fin region than in a middle portion of the doped sub-fin region, and the semiconductor fin structure having been formed by:
• forming a fin on a substrate such that the fin extends away from the substrate;
• forming an oxide material on the substrate and a portion of the fin that corresponds to a sub-fin region of the fin;
• forming a hard mask on a top-fin region of the fin that is disposed above the sub-fin region;
• exposing a surface of the sub-fin region by removing the oxide material from a surface of the sub-fin region and leaving a layer of the oxide material on the substrate;
• depositing a dopant material on the hard mask, the surface of the sub-fin region, and the layer of the oxide material on the substrate;
• removing the hard mask from the top-fin region to expose a surface of the top-fin region;
• and
• removing the layer of the oxide material from the substrate.

A computing device comprising:

• a memory device;
• and
• a processor coupled to the memory device, the processor including a semiconductor device comprising at least one semiconductor fin structure, the at least one semiconductor fin structure including:
• a plurality of fins disposed on a substrate wherein individual fins of the plurality of fins are laterally separated from other fins of the plurality of fins, wherein individual fins of the plurality of fins extend away from the substrate, wherein individual fins of the plurality of fins include a doped sub-fin region that is disposed on the substrate and an undoped top-fin region that is disposed on the sub-fin region, and wherein the plurality of fins act as channel regions of one or more transistors;
• and
• a reflowable dielectric material that substantially covers the doped sub-fin region and the substrate, and
• the at least one semiconductor fin structure having been formed by:
• forming a fin on a substrate such that the fin extends away from the substrate;
• forming an oxide material on the substrate and a portion of the fin that corresponds to a sub-fin region of the fin;
• forming a hard mask on a top-fin region of the fin that is disposed above the sub-fin region;
• exposing a surface of the sub-fin region by removing the oxide material from a surface of the sub-fin region and leaving a layer of the oxide material on the substrate;
• depositing a dopant material on the hard mask, the surface of the sub-fin region, and the layer of the oxide material on the substrate;
• removing the hard mask from the top-fin region to expose a surface of the top-fin region;
• and
• removing the layer of the oxide material from the substrate.