In-Situ Electrical Biasing of Electrically Connected TEM Lamellae with Embedded Nanodevices

In response to a continually rising demand for high performance and low-cost devices, and equally driven by competitivity, the microelectronics industry excels in meeting innovation challenges and further miniaturizing products. However, device shrinkage and the increasing complexity of device architecture require local quantitative studies. In this paper, we demonstrate with a case study on a nanocapacitor, the capability of transmission electron microscopy in electron holography mode to be a unique in-situ technique for mapping electric fields and charge distributions on a single device.

Influence of moisture concentration and hydrophobic material on induced stress in FCBGA package under reflow

Purpose This paper focuses on the fluid-structure interaction (FSI) analysis of moisture induced stress for the flip chip ball grid array (FCBGA) package with hydrophobic and hydrophilic materials during the reflow soldering process. The purpose of this paper is to analyze the influence of moisture concentration and FCBGA with hydrophobic material on induced pressure and stress in the package at varies times. Design/methodology/approach The present study analyzed the warpage deformation during the reflow process via visual inspection machine (complied to Joint Electron Device Engineering Council standard) and FSI simulation by using ANSYS/FLUENT package. The direct concentration approach is used to model moisture diffusion and ANSYS is used to predict the Von-Misses stress. Models of Test Vehicle 1 (similar to Xie et al., 2009b) and Test Vehicle 2 (FCBGA package) with the combination of hydrophobic and hydrophilic materials are performed. The simulation for different moisture concentrations with reflows process time has been conducted. Findings The results from the mechanical reliability study indicate that the FSI analysis is found to be in good agreement with the published study and acceptable agreement with the experimental result. The maximum Von-Misses stress induced by the moisture significantly increased on FCBGA with hydrophobic material compared to FCBGA with a hydrophilic material. The presence of hydrophobic material that hinders the moisture desorption process. The analysis also illustrated the moisture could very possibly reside in electronic packaging and developed beyond saturated vapor into superheated vapor or compressed liquid, which exposed electronic packaging to higher stresses. Practical implications The findings provide valuable guidelines and references to engineers and packaging designers during the reflow soldering process in the microelectronics industry. Originality/value Studies on the influence of moisture concentration and hydrophobic material are still limited and studies on FCBGA package warpage under reflow process involving the effect of hydrophobic and hydrophilic materials are rarely reported. Thus, this study is important to effectively bridge the research gap and yield appropriate guidelines in the microelectronics industry.

Recent Advances in Sequential Infiltration Synthesis (SIS) of Block Copolymers (BCPs)

In the continuous downscaling of device features, the microelectronics industry is facing the intrinsic limits of conventional lithographic techniques. The development of new synthetic approaches for large-scale nanopatterned materials with enhanced performances is therefore required in the pursuit of the fabrication of next-generation devices. Self-assembled materials as block copolymers (BCPs) provide great control on the definition of nanopatterns, promising to be ideal candidates as templates for the selective incorporation of a variety of inorganic materials when combined with sequential infiltration synthesis (SIS). In this review, we report the latest advances in nanostructured inorganic materials synthesized by infiltration of self-assembled BCPs. We report a comprehensive description of the chemical and physical characterization techniques used for in situ studies of the process mechanism and ex situ measurements of the resulting properties of infiltrated polymers. Finally, emerging optical and electrical properties of such materials are discussed.

Mechanism of Electronegativity Heterojunction of Nanometer Amorphous-Boron on Crystalline Silicon: An Overview

The discovery of the extremely shallow amorphous boron-crystalline silicon heterojunction occurred during the development of highly sensitive, hard and robust detectors for low-penetration-depth ionizing radiation, such as ultraviolet photons and low-energy electrons (below 1 keV). For many years it was believed that the junction created by the chemical vapor deposition of amorphous boron on n-type crystalline silicon was a shallow p-n junction, although experimental results could not provide evidence for such a conclusion. Only recently, quantum-mechanics based modelling revealed the unique nature and the formation mechanism of this new junction. Here, we review the initiation and the history of understanding the a-B/c-Si interface (henceforth called the “boron-silicon junction”), as well as its importance for the microelectronics industry, followed by the scientific perception of the new junctions. Future developments and possible research directions are also discussed.

Evaluation of interface toughness of bi-material Ni/Al by molecular dynamics method

Bi-materials in submicron scale have been widely used in many industries, especially in the microelectronics industry. Due to the different deformation between the two material layers, damage usually occurs on the surface between the two material layers. In this paper, the Molecular dynamics (MD) method is used to investigate the mechanical properties of bi-material Ni/Al under the tensile strain. The examined Ni/Al structure has dimensions of 10.90 nm x 5.27 nm x 4.22 nm/10.93 nm x 5.26 nm x 4.21 nm, with strain rates of 1.83x108s-1, 5.48x108s-1, 1.83x109s-1 and 5.48x109s-1, respectively. The interactions between the atoms in the system are described by the EAM (Embedded Atom Method). The calculated results show that Young's modulus of bi-material Ni/Al does not change under the various strain rates, while the fracture strength of Ni/Al increases with increasing of the strain rates. In addition, the effects of load position and temperature on the fracture strength of Ni/Al are also investigated. With the strain rate of 1.83x108 s-1, the fracture strength of Ni/Al at 100oK and 700oK is 6.6 GPa and 4.3 GPa, respectively. The obtained results of the study are helpful in the design and fabrication of devices based on the bi-material Ni/Al.

Microcantilever: Dynamical Response for Mass Sensing and Fluid Characterization

A microcantilever is a suspended micro-scale beam structure supported at one end which can bend and/or vibrate when subjected to a load. Microcantilevers are one of the most fundamental miniaturized devices used in microelectromechanical systems and are ubiquitous in sensing, imaging, time reference, and biological/biomedical applications. They are typically built using micro and nanofabrication techniques derived from the microelectronics industry and can involve microelectronics-related materials, polymeric materials, and biological materials. This work presents a comprehensive review of the rich dynamical response of a microcantilever and how it has been used for measuring the mass and rheological properties of Newtonian/non-Newtonian fluids in real time, in ever-decreasing space and time scales, and with unprecedented resolution.

Breaking the absorption limit of Si toward SWIR wavelength range via strain engineering

Silicon has been widely used in the microelectronics industry. However, its photonic applications are restricted to visible and partial near-infrared spectral range owing to its fundamental optical bandgap (1.12 eV). With recent advances in strain engineering, material properties, including optical bandgap, can be tailored considerably. This paper reports the strain-induced shrinkage in the Si bandgap, providing photosensing well beyond its fundamental absorption limit in Si nanomembrane (NM) photodetectors (PDs). The Si-NM PD pixels were mechanically stretched (biaxially) by a maximum strain of ~3.5% through pneumatic pressure–induced bulging, enhancing photoresponsivity and extending the Si absorption limit up to 1550 nm, which is the essential wavelength range of the lidar sensors for obstacle detection in self-driving vehicles. The development of deformable three-dimensional optoelectronics via gas pressure–induced bulging also facilitated the realization of unique device designs with concave and convex hemispherical architectures, which mimics the electronic prototypes of biological eyes.