The perfect pattern transfer from mask to substrate during the plasma‐etching process is strongly limited by the charging effect on the mask surface, which is increased by the accumulation of negative charges on the surface. These are mainly caused by high‐velocity isotropic electrons impinging on the mask surface faster than ions. These anisotropic ions thus bombard the undesired locations of the mask under the influence of the electric field (E‐field) established by electrons. This problem leads to significant damages to the mask pattern and causes deformations of etched features due to failure pattern transfer. This study examined that electron angular distribution (EAD; relative to the vertical direction, which can be regulated by voltage waveform tailoring) displays a close relationship with the mask pattern damage. Based on a modeling framework that consists of a surface etching module, a surface charging module, and a profile evolution module, the effects of changing the EAD on distributions of spatial E‐field and etching rate were studied focusing on an isolated rough mask hole surface. It is revealed that by narrowing the EAD shape, the E‐field strength and the etching rate around the mask hole edge can be reduced strongly, meanwhile, the number of electrons penetrating into the bottom of the trench can be greatly increased. These developments will supposedly reduce the mask‐pattern damage and improve the etching of high‐aspect‐ratio (HAR) features into the substrate. The simulated evolution rates of profile of a rough mask hole and the profile of E‐field strength inside the hole under various EAD shapes verify the above conclusions. The mechanism behind these results was analyzed systematically. This study provides a significant point for further investigation into the optimization of the etching technique.

Polystyrene (PS) nanoparticle films with non-close-packed arrays were prepared by using ion beam etching technology. The effects of etching time, beam current, and voltage on the size reduction of PS particles were well investigated. A slow etching rate, about 9.2 nm/min, is obtained for the nanospheres with the diameter of 100 nm. The rate does not maintain constant with increasing the etching time. This may result from the thermal energy accumulated gradually in a long-time bombardment of ion beam. The etching rate increases nonlinearly with the increase of beam current, while it increases firstly then reach its saturation with the increase of beam voltage. The diameter of PS nanoparticles can be controlled in the range from 34 to 88 nm. Based on the non-close-packed arrays of PS nanoparticles, the ordered silicon (Si) nanopillars with their average diameter of 54 nm are fabricated by employing metal-assisted chemical etching technique. Our results pave an effective way to fabricate the ordered nanostructures with the size less than 100 nm.

Coupled nano-mechanical resonators (NRs) have recently attracted great attention for both practical applications and fundamental studies. As a preparation step, it is needed to cool the coupled NRs to their ground states. In this paper, we investigate the coupled mechanical resonators cooling by employing the covariance approach for the identical and nonidentical cases, special attention is paid to the strong optomechanical coupling regime. Using numerical investigations, we show that the two coupled NRs can be simultaneously cooled down to nearly the vibrational ground state with the strong optomechanical coupling with the RWA. For these reasons, our scheme may provide a new paradigm for the coherent manipulation of NRs in the strong optomechanical coupling regime.

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A Multi-outlet single photon quantum router between microwave and optical frequency domain is investigated in a system consisting of a superconducting microwave cavity and an optical nanomechanical cavity coupled to a commom nanomechanical resonator (NAMR). It is demonstration that the single-photon of optical frequency can be routed into three different output ports by adjusting microwave power. More importantly, the two output signals can be selected according to microwave power. Meanwhile, we also show that thermal noise will be insignificant for the optical performance of the single-photon router at temperature of the order of 20 mK. Our proposal may have paved a new avenue towards multi-channel router and quantum network.