3‐D Nanofabrication of Silicon and Nanostructure Fine‐Tuning via Helium Ion Implantation

Abstract

Despite the continued scaling down of semiconductor manufacturing, traditional lithography‐based nanofabrication only produces thin film structures, not 3‐D shapes. 3‐D nanofabrication remains a major challenge, especially for semiconductor materials. Most 3‐D nanofabrication techniques, such as two‐photon printing and stereolithography, mostly work for polymer materials, not solid‐state semiconductor materials. Here, a method capable of fabricating sophisticated 3‐D nanostructures of silicon based on the subsurface swelling phenomenon using focused helium ion swelling is reported. Silicon nanosphere arrays, hierarchical nanospheres mimicking compound lenses, nano‐Taichi symbols, three‐layer nanotowers, and nanopumpkins have been demonstrated, which are challenging for existing nanofabrication technology. The produced silicon nanostructures exhibit super small surface roughness as small as 0.1 nm, two orders of magnitude better than existing 3‐D nanofabrication technologies normally above 10 nm. The super small surface roughness opens doors for many exciting applications in photonics, indicating small photon losses. Moreover, it is demonstrated ultraprecise fine‐tuning of critical dimensions of ready‐made nanostructures or nanodevices, such as tuning the tilting angle of the tip on the atomic force microscopy probe and reducing the nanogap between two metal electrodes from 200 to 4 nm, which is promising for improving nanodevice performances by tuning the critical dimensions to desired ranges.

A wear-resistant silicon nano-spherical AFM probe for robust nanotribological studies

“…3(c). Practically, the new nano-spherical probe is well suited for contact mode AFM operation since it is ultra-smooth (B0.1 nm roughness) 55 and does not wear easily, whereas it is very difficult to complete a contact mode full scan using the sharp probe (without replacement) because it can easily wear off.…”

Efficient Broadband Light Absorption in a Bioinspired Silicon Photonic Structure

“…If we simplify the structure, it consists of a central semicylinder and 6 nanocylinders on top of the central semicylinder. A silicon semicylinder can be fabricated using the technique mentioned by M. N et al 47 The top nanocylinders (nanopillars) can be fabricated and suspended following the approach mentioned by Li et al 48 The next step is to transfer the cylinders to a silicon chip�this can be done using a focused ion beam tungsten probe using a method similar to the method mentioned in the work by Kim et al 49 Another method that can be used is the 3D nanofabrication using the high-energy focused helium ion beam technique mentioned by Wen et al 50 3.3. Current−Voltage Characteristics of the Optimized Photonic Structure.…”

Enhancing thermoelectric properties of isotope graphene nanoribbons via machine learning guided manipulation of disordered antidots and interfaces

“…Subsequently, we will increase the ZT of AGNRs by introducing heterojunction structures [88,95]. The size of the optimal AGNR structure is 25.56 nm × 1.48 nm, and the nanopore diameter is 0.57 nm, whilst the state-of-the-art helium ion microscope has a super small beam spot as small as 0.5 nm [96]. Thus, the aperiodic isotopic superlattice preparation may be achieved via chemical vapor deposition technology by controlling pulsed signals to allow different isotopic carbon source gases into the reaction chamber.…”