Novel Vertically-Stacked Tensily-Strained Ge0.85Si0.15 GAA n-Channels on a Si Channel with SS=76mV/dec, DIBL=36mV/V, and Ion/Ioff=1.2E7
Journal
2019 International Symposium on VLSI Technology, Systems and Application, VLSI-TSA 2019
Date Issued
2019
Author(s)
Abstract
The tensily strained high Ge content (85%) GeSi multi-channels stacked on the Si channel with channel size optimization have good subthreshold behaviors (SS, DIBL, and \mathrm{I}-{\mathrm{off}}), and meanwhile maintain high \mathrm{I}-{\mathrm{on}}. By narrowing GeSi channel, the bandgap of the GeSi can be increased by quantum confinement and the short channel effect can be suppressed. This also causes the more positive \mathrm{v}-{\mathrm{t}} for GeSi than Si. As a result, \mathrm{SS}=76\mathrm{mV}/\mathrm{dec}, \mathrm{DIBL}=36\ \mathrm{mV}/\mathrm{V} can be achieved due to the benefit of superior subthreshold behaviors of the Si channel underneath. The \mathrm{I}-{\mathrm{on}}/\mathrm{I}-{\mathrm{off}} is improves to be 1.2E7. The high \mathrm{I}-{\mathrm{on}}=44\mu \mathrm{A} perstack at \mathrm{Vov}= \mathrm{V}-{\mathrm{DS}}=1\mathrm{V}, is contributed from both the GeSi and Si channels, and it is further enhanced to 46\ \mu \mathrm{A} by the external strain. The relatively low flicker noise indicates that the novel structure can mitigate the reliability issue of GeSi channels by the highly reliable Si channel underneath.
Type
conference paper