The eight stacked Ge 0.9 Sn 0.1 ultrathin bodies down to 3 nm with high <inline-formula> <tex-math notation="LaTeX">{I}_{\text {ON}}/I_{\text {OFF}} </tex-math></inline-formula> and eight stacked Ge 0.9 Sn 0.1 thick nanosheets with high <inline-formula> <tex-math notation="LaTeX">{I}_{\text {ON}} </tex-math></inline-formula> per stack are demonstrated. For the eight stacked Ge 0.9 Sn 0.1 ultrathin bodies, the 50 epilayers, including Ge 0.9 Sn 0.1 channels, double Ge 0.97 Sn 0.03 /Ge (8 nm/3 nm) caps, heavily B-doped (~2E21 cm −3 ) Ge sacrificial layers (SLs), and undoped Ge buffer were epitaxially grown to reach high inter-channel uniformity with the co-optimization of epitaxy and radical-based highly selective isotropic dry etching (HiSIDE). The thin double Ge 0.97 Sn 0.03 caps can provide sufficient etching selectivity and stabilize the channel to prevent the channels from bending and buckling. The neutral radicals can isotropically etch the Ge 0.97 Sn 0.03 /Ge caps, Ge:B SLs, and Ge buffer to form the highly uniform eight stacked Ge 0.9 Sn 0.1 ultrathin bodies. The record <inline-formula> <tex-math notation="LaTeX">{I}_{\text {ON}}/{I}_{\text {OFF}} </tex-math></inline-formula> of 1.4 <inline-formula> <tex-math notation="LaTeX">\times 10^{{7}} </tex-math></inline-formula> at <inline-formula> <tex-math notation="LaTeX">{V}_{\text {DS}} \,\,=\,\,-0.05 </tex-math></inline-formula> V is achieved among GeSn 3-D pFETs due to the quantum confinement. For the eight stacked Ge 0.9 Sn 0.1 thick nanosheets, the record <inline-formula> <tex-math notation="LaTeX">{I}_{\text {ON}} </tex-math></inline-formula> of 92 <inline-formula> <tex-math notation="LaTeX">\mu \text{A} </tex-math></inline-formula> per stack at <inline-formula> <tex-math notation="LaTeX">{V}_{\text {OV}} = {V}_{\text {DS}} = -0.5 </tex-math></inline-formula> V is achieved among GeSn 3-D pFETs. Thick nanosheets can provide higher mobility than ultrathin bodies due to the reduced surface roughness scattering.