Samsung (Japan)

A dual band rectenna with a compact dual loop antenna is presented for RF energy harvesting from the 2.4 GHz and 5.8 GHz Wi Fi bands. By designing the inductive dual loop antenna to be resonated with the capacitive rectifier diode at both bands, high antenna impedances of 5.2 kΩ at 2.42 GHz and 2.6 kΩ at 5.86 GHz are obtained for the rectifier. In the prototyped dual-band rectenna, rectification efficiencies of 83 % at 2.40 GHz and 56 % at 5.87 GHz with an input power of 0 dBm can be achieved, and are the highest efficiencies in both bands. This dual-band rectenna can be implemented in the smallest area.

We designed, fabricated, and characterized a full-color metalens using cross-shaped meta-atoms made of SiN. By controlling the phase distribution at three wavelengths (450 nm, 532 nm, and 633 nm) independently, we aimed to correct chromatic aberration and achieve a constant focal length for all three. By introducing correction terms to phase profiles for each wavelength, we demonstrated high focus performance through simulations. In the evaluation, we confirmed that the fabricated metalens successfully focused all three wavelengths, with the focal distance error within ±1%.

Depth profile of the dopant concentration in silicon substrate has a crucial influence on the electric characteristics that defines the device performance, whereas those profile has only been evaluated by destructive methods, most typically Secondary-Ion Mass Spectrometry (SIMS). We applied Terahertz Emission Spectroscopy (TES) that exploits charge carrier drift within the built-in potential structure to p-n junction structure in order to non-destructively extract the information about carrier dynamics and consequently the dopant profile. We prepared samples composed of Boron doped region as a p-Si and Phosphor doped region as a n-Si with a different p-n junction depth, and the TES evaluation was conducted illuminating the pump beam with the wavelength of 400nm. The obtained signals exhibit a clear difference among each sample in spite of the junction depth difference of as small as 15nm. The depth sensitivity of TES measurement was also investigated by utilizing carrier dynamics simulation, and clearly indicates the sensitivity to dopant depth profile, which is consistent with experimental TES signal. These results suggest that TES technology is very promising as in-line dopant profile measurement tool which is currently unrealistic with existing technologies and expected to greatly enhance the process control capability.

BaTiO3-CaTiO3 and SrTiO3-BaTiO3 core-shell nanocubes were synthesized through the surface reconstruction of BaTiO3 nanocubes, which involved the reaction of titanium oxide with Ca(OH)2, Sr(OH)2, or Sr(OH)2·8H2O in water at 100 °C. The core-shell structure comprised a BaTiO3 nanocube core and a CaTiO3 or SrTiO3 shell. The outermost layer with a perovskite structure also comprised CaTiO3 or SrTiO3, and its thickness was several hundred picometers. The thinnest layer was constructed of only one layer of CaTiO3 or SrTiO3. This is the first presented work on a core-shell nanocube with the outermost layer consisting of only CaTiO3 or SrTiO3 surrounding the BaTiO3 nanocube. The shells of CaTiO3 and SrTiO3 comprise a layer thickness of only one unit cell of ∼0.4 nm (400 pm). Thus, we demonstrate new research on nanocube surfaces on the picometer scale.

BiSb topological insulator is attractive for the spin current source in spin-orbit torque (SOT) magnetoresistive random access memory (MRAM) thanks to its giant charge-to-spin conversion efficiency. However, the large spin Hall angles have been reported so far only in BiSb deposited on top of Co/Pt and Co/Tb multilayers. In realistic SOT-MRAM application, it is essential to integrate BiSb to CoFeB/MgO junction with perpendicular magnetic anisotropy (PMA). Here, we report a large spin Hall angle of 2.8 in junctions of bottom BiSb and CoFeB/MgO with perpendicular magnetic anisotropy using a CrOx interfacial layer, which is suitable for use in magnetic tunnel junctions (MTJ). We demonstrated SOT magnetization switching by a small current density of 3.1 MA/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> at a pulse width of 50 μs, which is an order of magnitude smaller than that in heavy metals. Our work demonstrates the capability of integrating BiSb to CoFeB/MgO-based MTJ.

Using a combination of domain decomposition, massive parallelization and dimensionality reduction, a full chip-size stress simulation flow was developed. By application of shell elements in the Finite Element Method (FEM) framework, the prediction of the stress distribution in a Flash memory die (area about 1 cm²) back end of line (BEOL) metallization layers with nanometer scale precision becomes possible within a half day. Model calibration for several Flash memory product generations allowed more than 90 percent accuracy of crack defect formation probability prediction.

We developed the Si/O/H reactive force field parameter set and applied to silicon dry/wet oxidation process to understand the underlying physics of the thermal oxidation of the Si(100) surface. Through a systematic development of the Si/O parameter using the experimental data of the volumes of the SiO2 crystal as a reference, we reproduced the same result over the temperature range of 300–1300 K. With strategic tunings of parameters related to Si/O/H system, we carried out the simulation comparing the wet-and dry processes. A significant acceleration of the oxide film growth seen in the ‘in-situ-steam-generation (ISSG)’ is successfully represented. These properties of our model imply its applicability in wider scope. We compare our results with those obtained by using parameter set recently developed by other authors. Investigating the configuration of atoms near the interface of the SiO2 film, our model is found to be able to study the role of hydrogen atoms for the ISSG acceleration.

The Gd thickness dependence of spin–orbit torque (SOT) and critical current density of SOT switching in ferrimagnetic Gd/FeCo multilayers grown on a Ta seed layer was investigated and compared with the results on GdFeCo alloy/Ta bilayers. Critical current density of SOT switching J sw of Gd/FeCo multilayers was almost the same as those of the GdFeCo alloy films. The magnitudes of damping-like and field-like SOT effective fields, H DL and H FL, respectively, in Gd/FeCo multilayers were confirmed to increase near the compensation point, and the sign of H FL in Gd/FeCo multilayers was confirmed to change across the compensation point as well as GdFeCo alloy. Damping-like and field-like SOTs, estimated by multiplying the SOT effective fields by net magnetization, exhibited slightly smaller values for TM-dominant Gd/FeCo than for TM-dominant GdFeCo, while RE-dominant Gd/FeCo shows almost the same SOTs as RE-dominant GdFeCo.

We propose a new Magneto-optical Kerr effect (MOKE) system which consists of a dedicated electromagnet and a sensor for inspecting next generation memory, such as Spin-Transfer Torque Magnetoresistive Random Access Memory (STTMRAM). Conventional MOKE system is able to measure a magnetic hysteresis loop at a specific point by detecting the polarization rotation angle with changing the magnetic field intensity with the precision of less than 0.1deg on the reflected light. However, it takes several tens of seconds for measuring each point. We have demonstrated that inspection throughput of more than 1 wafer per hour with 2um pixel resolution can be achieved using proposed method called SCAN MOKE.