Doped amorphous layer 230 is formed by a suitable deposition process, such as chemical vapor deposition (CVD), physical vapor deposition (PVD), atomic layer deposition (ALD), high density plasma CVD (HDPCVD), metal organic CVD (MOCVD), remote plasma CVD (RPCVD), plasma enhanced CVD (PECVD), low-pressure CVD (LPCVD), atomic layer CVD (ALCVD), atmospheric pressure CVD (APCVD), spin coating, plating, other deposition method, or combinations thereof. In the depicted embodiment, doped amorphous layer 230 is conformally deposited over fin structure 220, such that thickness t is substantially uniform over exposed surfaces of fin structure 220 and/or substrate 210. Any suitable process (for example, an ion implantation process, a diffusion process, an in-situ doping process, or combinations thereof) can be implemented for doping the material deposited over the fin structure 220. In some implementations, a selective epitaxial growth (SEG) process is performed to grow a semiconductor material on exposed portions of fin structure 220, where dopants are introduced into the semiconductor material during the SEG process (for example, by adding dopants to a source material of the SEG process), thereby forming doped amorphous layer 230. The SEG process can implement CVD deposition techniques (for example, vapor-phase epitaxy (VPE), ultra-high vacuum CVD (UHV-CVD), LPCVD, and/or PECVD), molecular beam epitaxy, other suitable SEG processes, or combinations thereof. The SEG process can use gaseous precursors (for example, silicon-containing gases, such as SiH₄ and/or germanium-containing gases, such as GeH₄) and/or liquid precursors, which interact with a composition of fin structure 220. For example, in the depicted embodiment, where doped amorphous layer 230 is a doped amorphous silicon layer, the deposition process can expose fin structure 220 (and substrate 210) to a silicon-containing gas (for example, a silicon hydride containing gas (such as SiH₄, Si₂H₆, Si₃H₈, Si₄H₁₀, or combinations thereof)) and add dopants (for example, germanium, boron, arsenic, phosphorous, or combinations thereof) to the silicon-containing gas. In some implementations, doped amorphous layer 230 includes materials and/or dopants that achieve desired tensile stress and/or compressive stress in a channel region of FinFET device 200.