A Review: Inductively Coupled Plasma Reactive Ion Etching of Silicon Carbide

The inductively coupled plasma reactive ion etching (ICP-RIE) is a selective dry etching method used in fabrication technology of various semiconductor devices. The etching is used to form non-planar microstructures—trenches or mesa structures, and tilted sidewalls with a controlled angle. The ICP-RIE method combining a high finishing accuracy and reproducibility is excellent for etching hard materials, such as SiC, GaN or diamond. The paper presents a review of silicon carbide etching—principles of the ICP-RIE method, the results of SiC etching and undesired phenomena of the ICP-RIE process are presented. The article includes SEM photos and experimental results obtained from different ICP-RIE processes. The influence of O2 addition to the SF6 plasma as well as the change of both RIE and ICP power on the etching rate of the Cr mask used in processes and on the selectivity of SiC/Cr etching are reported for the first time. SiC is an attractive semiconductor with many excellent properties, that can bring huge potential benefits thorough advances in submicron semiconductor processing technology. Recently, there has been an interest in SiC due to its potential wide application in power electronics, in particular in automotive, renewable energy and rail transport.

Spin–orbit torque engineering in β-W/CoFeB heterostructures with W–Ta or W–V alloy layers between β-W and CoFeB

The spin–orbit torque (SOT) resulting from a spin current generated in a nonmagnetic transition metal layer offers a promising magnetization switching mechanism for spintronic devices. To fully exploit this mechanism, in practice, materials with high SOT efficiencies are indispensable. Moreover, new materials need to be compatible with semiconductor processing. This study introduces W–Ta and W–V alloy layers between nonmagnetic β-W and ferromagnetic CoFeB layers in β-W/CoFeB/MgO/Ta heterostructures. We carry out first-principles band structure calculations for W–Ta and W–V alloy structures to estimate the spin Hall conductivity. While the predicted spin Hall conductivity values of W–Ta alloys decrease monotonically from −0.82 × 103 S/cm for W100 at% as the Ta concentration increases, those of W–V alloys increase to −1.98 × 103 S/cm for W75V25 at% and then gradually decrease. Subsequently, we measure the spin Hall conductivities of both alloys. Experimentally, when β-W is alloyed with 20 at% V, the absolute value of the spin Hall conductivity considerably increases by 36% compared to that of the pristine β-W. We confirm that the W–V alloy also improves the SOT switching efficiency by approximately 40% compared to that of pristine β-W. This study demonstrates a new material that can act as a spin current-generating layer, leading to energy-efficient spintronic devices.

Effect of Surfactant in Gas Dissolved Cleaning Solutions on Acoustic Bubble Dynamics

Megasonic cleaning is one of the promising technologies to remove the particles during semiconductor processing. Acoustic bubble cavitation plays a key role in removing the particles. In this work, the effect of an anionic surfactant sodium dodecyl sulfate (SDS) on a bubble in the presence of hydrogen dissolved DIW water was studied. The bubble dynamics were observed using a high-speed camera. It was found that with the increase of surfactant the bubble characteristics were changed very significantly. Several parameters affecting the bubble dynamics were investigated.