Phase Stability, Phase Transformations, and Reactive Phase Formation in Electronic Materials XXI: Advanced Process and Materials for Electronics
Sponsored by: TMS Functional Materials Division, TMS: Alloy Phases Committee
Program Organizers: Hiroshi Nishikawa, Osaka University; Shih-kang Lin, National Cheng Kung University; Chao-hong Wang, National Chung Chung University; Chih Ming Chen, National Chung Hsing University; Jaeho Lee, Hongik University; Zhi-Quan Liu, Shenzhen Institutes of Advanced Technology; A.S.Md Abdul Haseeb, Bangladesh University of Engineering and Technology (BUET); Vesa Vuorinen, Aalto University; Ligang Zhang, Central South University; Sehoon Yoo, Korea Institute of Industrial Technology; Yu-Chen Liu, National Cheng Kung University; Ting-Li Yang, National Yang Ming Chiao Tung University
Tuesday 2:30 PM
March 1, 2022
Room: 303A
Location: Anaheim Convention Center
Session Chair: Jaeho Lee, Hongik University
2:30 PM Invited
A Critical Analysis of Joining Processes for NiTi Shape Memory Alloys: Boyd Panton1; Amirali Shamsolhodaei2; Jianxiong Li1; Anupam Vivek1; Glenn Daehn1; Peng Peng2; Y. N. Zhou2; 1The Ohio State University; 2University of Waterloo
Advanced engineered materials including high entropy alloys, ultrafine grained materials, and shape memory alloys are being developed to enable the next generation of industrial innovations. Shape memory alloys often need to be joined to dissimilar materials when manufacturing multifunctional devices. However, they suffer from critical weldability issues due to brittle intermetallic formation in these dissimilar applications. In addition to these weldability issues, the unique material properties resultant from solid-state phase transformations are extremely sensitive to the microstructure and chemical composition. An ideal welding solution would maintain the stability of the phase transformations at low and high fatigue cycles by not coarsening the microstructure nor altering the composition. New joining methods that limit heat input have proven capable of creating these ideal joints. This critical analysis will compare current state-of-the-art techniques for welding shape memory alloys such as laser welding, with emerging technologies including the laser impact welding process.
3:00 PM Cancelled
Effect of Detwinning on Tensile Strength of Nanotwinned Cu Films: Chiahung Lee1; 1National Central University
Tensile tests were carried on the electroplated Cu films with various densities of twin grain boundary. We found that the strength of the Cu films is highly related to the twin boundary density. The Cu film with a greater twin-boundary density has a larger fracture strength than the Cu film with a lesser twin-boundary density.Moreover, the de-twinning can be observed in the region where necking begins. Furthermore, with the analysis of the TEM images on the nano-twinned structure in the necking region of the fractured Cu films, the de-twinning mechanism attributes to two processes: (1) the ledge formation by the engagement of the dislocations with the twin boundaries and (2) the collapse of the ledges with the opposite twin-boundaries. In conclusion, the plastic deformation of nano-twinned Cu films is governed by the de-twinning of the nano-twinned structure.
3:20 PM
Effect of Vertical Interfaces on Phase Transformation Behavior of MoS2: Shayani Parida1; Arthur Dobley2; Barry Carter3; Avinash Dongare1; 1University of Connecticut; 2EaglePicher Technologies LLC; 3CINT, Sandia National Laboratories
Transition metal dichalcogenides (TMDs), have been widely explored as electrodes for lithium-ion batteries owing to their high capacities though certain TMDs, like, MoS2, phase transform upon ion intercalation during charge-discharge cycles, leading to reduction in battery longetivity. Van der Waal heterostructures of 2D materials possess properties quite different from the individual layers and can present opportunities to explore novel physical phenomena as well as prove to be a way to achieve superior device properties. In this study, density functional theory (DFT) is used to study heterostructures of MoS2 stacked with TMDs that do not phase transform upon ion intercalation, like, NbS2 and VS2. Designing such heterostructures with vertical interfaces is shown to be an effective strategy to curb propensity for phase transformation of MoS2 during Na and K intercalation. The origins of phase transformation in the heterostructure have been investigated by examining the ion binding and charge redistribution following intercalation.
3:40 PM
Comparison of NiCo and NiP Electroplating for Wear Resistant Probe Tip: Na-Young Kang1; Jaeho Lee1; 1Hongik University
Probe card is one of reliability testing tool in semiconductor system. MEMS technology is used in MEMS probe tip fabrication. As the size of semiconductor is getting smaller, the size of probe tip is decreased. Since the reliability of probe is dependent on the physical property of probe tip, the hard and wear resistant material is used. NiCo and Ni-P are candidate materials for this purpose. Both NiCo and Ni-P are fabricated through electroplating method. The physical properties of NiCo and Ni-P plating is dependent on the composition of the coatings as well as plating property such as grain size and residual stress. In this study the effect of plating bath conditions on the NiCo and Ni-P electroplatings are investigated and compared. The surface hardness and crystallography of coating is measured and compared. The effects of additive on the properties and contents of the coating is finally optimized.
4:00 PM
Morphological Effect of Patterned Sapphire Substrate on Efficiency of White-light Phosphor LED Package: Chia-Yueh Chou1; Cheng-Yi Liu1; 1National Central University
Six-facets patterned sapphire substrates (A-PSS) are manufactured by wet-etching regular semispherical patterned sapphire substrates (r-PSS). MOCVD GaN epitaxial LED structure was grown on the c-plane sapphire wafer, r-PSS, and A-PSS. Remarkably, the output power of the white-light packaged LED on the A-PSS is larger than the white-light packaged LED on the r-PSS. The Monte Carlo ray tracing simulation shows that, before and after silicone-lens encapsulating, the sidewall emission power ratio of LED on r-PSS decreases by 3.44% after encapsulating. On the other hand, the sidewall emission power ratio of the LED on A-PSS increases by 1.06% after encapsulating. The reason for LED on A-PSS having a less package loss and the white-light package efficiency than LED on r-PSS will be discussed. In conclusion, the light radiation distribution pattern defined by A-PSS is the key for the better white-light package efficiency of the LED on A-PSS.