Irfan Saadat

Carbon nanomaterials based TSVs for dual sensing and vertical interconnect application

We discuss fabrication and characterization of TSVs filled with carbon nano-materials (CNM) for dual function of sensing and vertical interconnect for hostile environment applications (Corrosive High Temperature and Pressure). Nano-composites, made by functionalization of CNTs were integrated using dispersion in epoxy resin and inkjet techniques to fill up the TSVs and provide sensing surface. The results reveal ability for the nano-composite to fill vias with electrical conductivity path and sensing established through the wafer backside.

ALD Al-doped ZnO Thin Film as Semiconductor and Piezoelectric Material: Characterization

This chapter covers the physical characterization of various aluminum-doped ZnO films that were synthesized. At high level, it includes electrical characterization followed by mechanical characterization. The electrical characterization includes Hall measurements to assess the mobility of the films, resistance measurements using special microfabricated patterned structures and carrier concentration measurements. The impact of Al doping on the ZnO thin films shows a very strong electrical signal, which manifested itself in the measured values of these parameters that are mentioned above. The results indicate the ability to tune various electrical parameters of the ZnO films through Al doping and growth temperature. Through response surface modeling, a sweet spot is identified where resistivity, mobility, and carrier concentration can be optimized to target values. While the mechanical characterization includes the piezoeffect characterization along with stress and strain analysis. This includes the comparison of different dielectrics films vis–vis ZnO films, followed by an assessment of 1D versus 2D piezoelectric structures including the wurtzite ZnO thin film. This includes the explanation of why these films have the highest piezoelectric coefficient in their class of materials and the role played by c-axis alignment in interpreting these observations. This establishes the criticality of assessing these quantities to come up with the right understanding and explanation for any observations seen in new class of thin films where the method of synthesis or doping is changed. Finally, the assessment of stress and strain in these film systems is presented with the role played by the substrate and the direction of the bending of the thin film. The experimental results include the design and fabrication of a “curved” stage that is used to induce the strains, and compute the associated stress generated, in quantifiable fashion to model the thin-film behavior.

Carbon Nanostructure‐Based Scale Sensors Using Inkjet Printing and Casting Techniques

In this chapter, the fabrication and characterization of scale sensor using carbon nanotubes (CNTs) are discussed. Two different methods are used to prepare the carbon nanomaterials for the sensor fabrication: CNT casting and the CNT inkjet printing. In addition, the sensors are integrated into Kelvin architectures. The electrical resistance of the carbon nanomaterial films is measured with and without adding a drop of brine to the surface of the film. The films are characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM), and energy dispersive X‐ray spectroscopy (EDS). Electrical resistance of the casted CNT films and five layers of CNT inkjet printing are found to be close to 40.0 kΩ and 1.00 kΩ, respectively. Adding one drop of brine solution on the surface of the casted CNT film and five layers of CNT inkjet printing changed the resistance by 50% and 75%, respectively. The resetting process is done for all sensors by soaking in deionized water (DI water) for some time, and the electrical resistance is measured and found to be close to the initial electrical resistance.

ALD Al-doped ZnO Thin Film as Semiconductor and Piezoelectric Material: Transistors and Sensors

Based on the results of Rizk and Saadat (The IoT Physical Layer, pp. 23–46, Springer, Berlin, 2018, [1], The IoT Physical Layer, pp. 47–68, Springer, Berlin, 2018, [2]), this chapter covers the use of Al-doped ZnO films as active channel material for TFT devices. It shows the need to have semiconducting behavior of the ZnO films and how this is modulated by the synthesis method, Al doping and synthesis temperature. Then, this chapter covers the process flow and goes over the unique challenges of fabricating on flexible substrate versus Si substrate and the associated mitigation techniques. These challenges include adhesion, film reliability, heat dissipation, and its low-temperature processing on flexible substrates. This is followed by the characterization of the TFT and its demonstration as best in its class, when it comes to this material system and associated fabrication constraints.

Effect of Saline Solution on the Electrical Response of Single Wall Carbon Nanotubes-Epoxy Nanocomposites

The effects of saline solution on the electrical resistance of single wall carbon nanotubes-epoxy nanocomposites have been investigated experimentally. Ultrasonic assisted fabricated 1.0% and 0.5 W/W% SWCNTs epoxy nanocomposites are integrated into a Kelvin structure by smear cast the nanocomposites on a glass wafer. Four metal pads are deposited on the nanocomposites using the beam evaporator and wires are tethered using soldering. The effect of saline solution on the electrical resistance of the nanocomposites is studied by adding drop of saline solution to the surface of the fabricated nanocomposites and measuring electrical resistance. Moreover, the nanocomposites are soaked completely into 3 wt.% saline solution and real-time measurement of the electrical resistance is conducted. It is found that a drop of saline solution on the surface of the nanocomposites film increases the resistance by 50%. Furthermore, the real-time measurement reveals a 40% increase in the resistance of the nanocomposites film. More importantly, the nanocomposites are successfully reset by soaking in DI water for four hours. This study may open the door for using SWCNTs epoxy nanocomposites as scale sensors in oil and gas industry.

Fabrication and characterization of low pressure graphene-based gas sensor

We discuss fabrication, characterization of graphene sensor for detection of different gases at low pressure. Two types of micro devices were fabricated, the first one is the kelvin structure and the second one is the membrane structure. Cavities were etched in the SiO 2 to form the membrane. Two techniques for synthesis of Graphene was used in this work: Chemical vapor deposition using Cu as catalyst and Inkjet printing. Electrical characterization for the graphene sensor was done in atmospheric pressure as well as Raman imaging.

Nanofluids Based on Carbon Nanostructures

A nanofluid consists in a liquid suspension of nanometer-sized particles. These fluids may contain (or not) surface-active agents to aid in the suspension of the particles. Nanometer-sized particles have higher thermal conductivity than the base fluids. Oxides, metals, nitrides, and nonmetals, like carbon nanotubes, can be used as nanoparticles in nanofluids. Water, ethylene glycol, oils, and polymer solutions can be used as base fluids. In this chapter, we summarize the recent studies of using CNTs and graphene to improve the thermal conductivity of nanofluids. Moreover, we refer to the studies about the effect of using magnetic fields on enhancing the thermal conductivity of nanofluids. Too much discrepancy about thermal conductivity of nanofluids can be found in the literature. For carbon nanofluids, unfortunately, no significant improvements on thermal conductivi‐ ty are observed using low concentrations. Different improvement percentages have been reported. This variation in the thermal conductivity can be attributed to many factors, such as particle size temperature, pH, or zeta potential. We believe that more research efforts need to be made in order to, first, improve the thermal conductivity of nano‐ fluids and, second, assess the effect of the different parameters and conditions on the thermal conductivity of nanofluids.

Nanowires piezoelectric constants determination using current-voltage measurements

This work demonstrates an original method using the electromechanical properties of the zinc oxide (ZnO) piezoelectric nanowires to characterize its piezoelectric voltage coefficient (d33). The proposed technique utilizes the current-voltage (IV) measurements coupled with the application of variable force to cause a change in the corresponding IV relationship. To conduct the IV measurements, the nanowire is integrated inside a field effect transistor (FET) to form the channel of the device, while it is suspended over a trench. The indentation of the nano-wire causes the mechanical deflection of the suspended nanowire which through the piezoelectric effect changes the IV characteristics of the FET. The extraction of the piezoelectric coefficient is done by modifying the standard FET IV model to incorporate the change in the channel length which is triggered by the piezoelectric behavior. Embedded within this change of length is piezoelectric coefficient and therefore, it becomes straightforward procedure to extract this coefficient from the changes in the IV characteristics.

Screening scenario-based analysis of modifications in planning of semiconductor manufacturing

The current work discusses the results obtained from the screening analysis using a model that dynamically manages supply contract modifications. These changes are related to customer order patterns at the wafer fabrication stage and at a mid-term master planning level. A demand-driven two-stage model is used to depict the operations of a typical silicon foundry, in which the objective is to find the optimal economic production plan based on the existing customer base, demand profile, capacity utilization status, and modification patterns. The first stage finds the initial pre-production optimal distribution plan for manufacturing activities among the existing facilities over the entire planning horizon. In the second stage, the plan attained from the first model is reviewed and tweaked based on changes on demand (i.e. rescheduling or additional requests) or even production capacity. Therefore, new scenario-specific production plans over a shorter planning horizon are created. The aggressive customer due-dates and customer-specific production represents the main process conditions. Several scenarios for a case study are evaluated to assist with the development of the supply contract clauses.