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This paper presents a 429 MHz flexible Lamb wave resonator based on lithium niobate thin films with a high figure of merit (FoM) of 205, which is about 10 times higher than the FoM of the flexible resonator presented in our previous work. The measured corresponding quality factor (Q) and electromechanical coupling coefficient (Kt2) are 1268 and 16.2%, respectively. The resonant frequency, Q, and Kt2 of the flexible resonator show maximum changes of only 0.11%, 0.37%, and 0.31%, respectively, under a repeated mechanical bending condition up to 10 000 times at a bending radius of 3 mm. We also found that FlexMEMS technology we proposed not only endows Lamb wave resonators with mechanical flexibility but also improves FoM by ∼180% compared to their counterpart, conventional Lamb wave resonators on rigid silicon substrates. The flexible resonators with much improved FoM will find applications as low-power radio frequency key components in emerging applications, especially Internet of Things.

Through Silicon vias (TSVs) are a key breakthrough in 3D technology to shorten global interconnects and enable the heterogeneous integration. However, TSVs also introduce an important source of noise coupling arising from electrical coupling between TSVs and the active devices. This paper investigates the TSV noise coupling to active devices including both FinFETs and planar transistors based on twoport S-parameter measurements up to 40 GHz. The measurements clearly show that nFinFETs have better noise coupling immunity than planar nNMOSFETs. The dominant coupling mechanisms were also identified for both types of active devices.Moreover, calibrated TCAD models were developed. We show that via-last TSV architectures with thick liners ("donut TSVs") and scaled TSV diameters reduce the noise coupling to active devices. Finally, both coupling and stress induced saturation current variations as a function of TSV to active devices distance were investigated. This allows us to propose a novel model for the TSV Keep Out Zone (KOZ) including electromagnetic coupling effects.978-1-4799-8609-5/15/$31.00 ©2015 IEEE

The effect of the source/drain compressive stress on the mechanical stability of stacked Si nanosheets (NS) during the process of channel release has been investigated. The stress of the nanosheets in the stacking direction increased first and then decreased during the process of channel release by technology computer-aided design (TCAD) simulation. The finite element simulation showed that the stress caused serious deformation of the nanosheets, which was also confirmed by the experiment. This study proposed a novel channel release process that utilized multi-step etching to remove the sacrificial SiGe layers instead of conventional single-step etching. By gradually releasing the stress of the SiGe layer on the nanosheets, the stress difference in the stacking direction before and after the last step of etching was significantly reduced, thus achieving equally spaced stacked nanosheets. In addition, the plasma-free oxidation treatment was introduced in the multi-step etching process to realize an outstanding selectivity of 168:1 for Si0.7Ge0.3 versus Si. The proposed novel process could realize the channel release of nanosheets with a multi-width from 30 nm to 80 nm with little Si loss, unlocking the full potential of gate-all-around (GAA) technology for digital, analog, and radio-frequency (RF) circuit applications.