First Vertically Stacked, Compressively Strained, and Triangular Ge0.91Sn0.09pGAAFETs with High $\mathbf{I_{ON}}$ of $\mathbf{19.3}\mu \mathbf{A}\ \mathbf{at}\ \mathbf{V_{OV}}=\mathbf{V}_{\mathbf{DS}}=\mathbf{-0.5V},\ \mathbf{G}_{\mathbf{m}}$ of $\mathbf{50.2}\mu \mathbf{S}$ at $\mathbf{V_{DS}}=\mat

The natural etching stop on {111} facets yields the small dangling bond density and roughness, enabling low SS and high $\text{I}_{\text{ON}}$ on {111} sidewalls of the GAA channels. In addition, the $\sim 2\%$ uniaxial compressive strain and $[\text{Sn}]=9\%$ in the channel can reduce the hole effective mass. As a result, 50% improvement of $\text{I}_{\text{ON}}= 120\mu \text{A}/\mu\text{m}$ (perimeter), and 71% improvement of $\text{G}_{\text{m}}=312\mu \text{S}/\mu\text{m}$ are achieved than our previous 3 stacked GeSn {001} nanosheets. Record high $\text{I}_{\text{ON}}$ of $19.3\mu \text{A}$ per stack at $\text{V}_{\text{OV}}=\text{V}_{DS}=-0.5\text{V}$ and record $\text{G}_{\text{m}}$ of $50.2\mu\text{S}$ per stack at $\text{V}_{\text{DS}}=-0.5\text{V}$ among all GeSn FinFETs and GAAFETs are achieved. The $\text{SS}_{\text{lin}}$ as low as S4mV/dec is also obtained, 22% reduction than our previous work.