Non-planar surface may cause incorrect transfer of patterns during lithography. In today’s IC manufacturing, chemical mechanical polishing (CMP) is used for topographical planarization. Since polish rates for metals and oxides are different, dummy metal fills in layout is used to minimize post-CMP thickness variability. Traditional metal fill solutions focus on satisfying density target determined by layout density analysis techniques. These solutions may potentially reduce yield by increasing probability of failure (POF) due to particulate defects and also impact design performance. Layout design solutions that minimize POF and also improve surface planarity via dummy fill insertions have competing requirements for line spacing. In this thesis, I present a formulation to balance these competing goals and provide a comparative study of greedy (or fixed spacing), variable spacing and LP formulation based fill insertions based on scalability and quality of solution. I extend the variable spacing fill to allow non-preferred direction routing of fill patterns in order to further improve the CA. Traditional fill solutions impact design performance due to increase coupling capacitance on signal nets. I present a fill insertion algorithm that minimizes this increase in coupling capacitance due to fill. Finally, I extend the critical area based solution to include SRAF insertion in order to account for optical diffraction in lithography. Thus the proposed solution addresses both lithography and particulate related defects and minimizes the fill impact on design performance at the same time. Experimental results based on layout of ISCAS 85 benchmark circuits show that the variable spacing and the LP formulation based fill insertion techniques result in substantially reduced critical area while satisfying the layout density and uniformity criteria. The coupling capacitance minimization fill solution reduces the fill impact on coupling capacitance while at the same time minimizing the critical area.

This thesis presents the design, layout, and measurements of a bi-directional amplifier with variable vector (in-phase / quadrature) gain control that will be part of an electronically steered phased array system. The electronically steered phased array has many advantages over the conventional mechanically steered antennas including rapid scanning of the beam and adaptively creating nulls in desired locations. The 10-bit bi-directional Vector Variable Gain Amplifier (VVGA) is part of the transmit and receive module of each antenna element where transmit and receive functionality is determined through a simple switch. The VVGA performs amplification of the IF IQ pair by an adjustable complex coefficient. At receive, the VVGA functions as a Vector Variable Gain Current Amplifier (VVGCA) and at transmit, the VVGA functions as a Vector Variable Gain Transadmittance Amplifier (VVGTA). Design procedure, layout entry, schematic and parasitic extracted simulation results, and measurements are presented in this thesis.

Quantum-Dot Cellular Automata (QCA) is currently being investigated as an alternative to CMOS technology. There has been extensive study on a wide range of circuits from simple logical circuits such as adders to complex circuits such as 4-bit processors. At the same time, little if any work has been done in considering the possibility of reconfiguration to reduce power in QCA devices. This work presents one of the first such efforts when considering reconfigurable QCA architectures which are expected to be both robust and power efficient. We present a new reconfiguration scheme which is highly robust and is expected to dissipate less power with respect to conventional designs. An adder design based on the reconfiguration scheme will be presented in this thesis, with a detailed power analysis and comparison with existing designs. In order to overcome the problems of routing which comes with reconfigurability, a new wire crossing mechanism is also presented as part of this thesis.

Here we present the design, assembly and successful ion trapping of a room-temperature ion trap system with a custom designed and fabricated surface electrode ion trap, which allows for rapid prototyping of novel trap designs such that new chips can be installed and reach UHV in under 2 days. The system has demonstrated success at trapping and maintaining both single ions and cold crystals of ions. We achieve this by fabricating our own custom surface Paul traps in the UMass Amherst cleanroom facilities, which are then argon ion milled, diced, mounted and wire bonded to an interposer which is placed in an ultra-high vacuum chamber and baked in a conventional oven for 46 hours. We demonstrate the system’s ability to confine strontium ions and present preliminary data towards calibrating the ion trap parameters for reduced heating rates. Future work will see the system being used to study the effects of various trap geometries, process fabrication steps and surface treatments on anomalous heating rates, and for portable quantum sensing applications, as an optical atomic clock.

<p>Sensor technology is evolving rapidly, offering new opportunities for environmental data collection. Yet, despite the large number of sensors now available, there is a lack of logging platforms that can be used to operate these sensors in situ. To address this shortfall, River Restoration Intelligence and Verification (RRIV) has developed an environmental data logger that meets the needs of the environmental sensing community. This platform has several advantages that reduce the time, effort, and technical know-how required to deploy environmental sensors. An extensive low-power mode is available, and hardware such as a real-time clock with an independent power source is incorporated. A driver system has been developed that allows users to incorporate sensors into the platform with minimal effort. RRIV loggers also include a command line interface that allows user to add or remove sensors, calibrate sensors, or configure deployments without the need for C/C++ programming, something that is not possible with out-of-the-box microcontrollers such as Arduino and ST Nucleo products. The technology incorporated into RRIV and how it is applied and deployed in the field is described. This includes a description of power consumption. Protocols and descriptions of case construction are also included. RRIV loggers configured to monitor carbon dioxide and methane are used to demonstrate how this platform is used in the field.</p>

With the requirement to store and transmit information efficiently, an ever increasing number of uses of data compression techniques have been generated in diverse fields such as television, surveillance, remote sensing, medical processing, office automation, and robotics. Rapid increases in processing capabilities and the speed of complex integrated circuits make data compression techniques a prime candidate for application in the areas mentioned above. This report addresses, from a theoretical viewpoint, three major data compression techniques, Pixel Coding, Predictive Coding, and Transform Coding. It begins with a project description and continues with data compression techniques, focusing on Differential Pulse Code Modulation.

The purpose of this study is to investigate RF or Radio Frequency energy as a viable alternative to traditional heating methods for the purpose of curing resins used in resin infusion molding, a molding system for polymeric composites. Traditional heating/curing methods include technologies such as room temperature, oven, microwave, infrared, and ultraviolet. Although RF curing provides far more advantages than disadvantages, its implementation into a manufacturing process can be challenging. Specifically, three critical elements must be present in order for RF to function in a manner that is profitable to the manufacturer. Those elements are: (1) the proper generator (voltage and frequency), (2) the correct electrode configuration, and (3) the appropriate material sensitizer (amount and type). There is also the consideration of initial capital investment; which is by no means insignificant. However, if all 3 elements are present, the benefits can be immediate and numerous. Potential advantages include the following: improved part quality through penetrating and uniform heating; competitive, if not superior, material physical properties; and drastically reduced curing times. Other potential advantages include floor space savings, high energy efficiency, and increased operational flexibility. For the purpose of this thesis, experimentation will be conducted to first confirm and then, if successful, quantitatively capture the reduction in curing time. Physical properties will also be measured using tensile testing to determine whether or not RF curing can facilitate minimal loses in the material's physical properties.

ABSTRACT Fabrication and Characterization of Torsional Micro-Hinge Structures Mike Marrujo There are many electronic devices that operate on the micrometer-scale such as Digital Micro-Mirror Devices (DMD). Micro actuators are a common type of DMD that employ a diaphragm supported by torsional hinges, which deform during actuation and are critical for the devices to have high stability and reliability. The stress developed within the hinge during actuation controls how the actuator will respond to the actuating force. Electrostatically driven micro actuators observe to have a fully recoverable non-linear viscoelastic response. The device consists of a micro-hinge which is suspended by two hinges that sits inside a micro machined well. To achieve a specific angle of rotation when actuated, the mechanical forces need to be characterized with a range of different forces applied to the edge of the micro-hinge. This research investigates the mechanical properties and the amount of force needed to rotate to specific angles by comparing theoretical performance to experimentally measured values. Characterizing the mechanical forces on the micro-hinge will further the understanding of how the device operates under a specific applied force. The material response to the amount of stress within the hinges will control the amount of actuation that is achieved by that force. The test devices were fabricated using common semiconductor fabrication techniques. The micro-hinge device was created on a 500µm, double-sided polished, single crystal (100) silicon wafer. In order to create this device, both wet etching and dry etching techniques were employed to produce an 8µm thick plate structure. The bulk etching of 480µm was achieved by wet etching down into the silicon (Si) to create the wells. Dry etching was used for its high precision to release the micro-hinge structure. Once fabricated, the micro-hinge actuators were tested using a Technics turntable arm with a built in micrometer that applied a constant force while measuring the displacement of the actuator. The rotation of the hinge was measured by reflecting a Helium-Neon (HeNe) laser beam off a mirror, which is attached to the pivot of the arm that’s applying the force, and any type of displacement was recorded with a Photo Sensitive Device (PSD). The test stand applied a small force which replicated the amount of electrostatic forces needed to achieve a specific degree of rotation. Results indicate that the micro-hinge achieved a repeatable amount of rotation when forces were applied to it. The micro-hinge would endure deformation when too much force would be applied and yield a maximum amount of force allowed.

Gallium nitride (GaN) light emitting diodes (LED) embody a large field of research that aims to replace inefficient, conventional light sources with LEDs that have lower power, higher luminosity, and longer lifetime. This thesis presents an international collaboration effort between the State Key Laboratory for Mesoscopic Physics in Peking University (PKU) of Beijing, China and the Electrical Engineering Department of California Polytechnic State University, San Luis Obispo. Over the course of 2 years, Cal Poly’s side has simulated GaN LEDs within the pure blue wavelength spectrum (460nm), focusing specifically on the effects of reflection gratings, transmission gratings, top and bottom gratings, error gratings, 3-fold symmetric photonic crystal, and 2-fold symmetric nano-imprinted gratings. PKU used our simulation results to fabricate GaN high brightness LEDs from the results of our simulation models. We employed the use of the finite difference time domain (FDTD) method, a computational electromagnetic solution to Maxwell’s equations, to measure light extraction efficiency improvements of the various grating structures. Since the FDTD method was based on the differential form of Maxwell’s equations, it arbitrarily simulated complex grating structures of varying shapes and sizes, as well as the reflection, diffraction, and dispersion of propagating light throughout the device. We presented the optimized case, as well as the optimization trend for each of the single grating structures within a range of simulation parameters on the micron scale and find that single grating structures, on average, doubled the light extraction efficiency of GaN LEDs. Photonic crystal grating research in the micron scale suggested that transmission gratings benefit most when grating cells tightly pack together, while reflection gratings benefit when grating cells space further apart. The total number of grating cells fabricated on a reflection grating layer still affects light extraction efficiency. For the top and bottom grating structures, we performed a partial optimization of the grating sets formed from the optimized single grating cases and found that the direct pairing of optimized single grating structures decreases overall light extraction efficiency. However, through a partial optimization procedure, top and bottom grating designs could improve light extraction efficiency by 118% for that particular case, outperforming either of the single top or bottom grating cases alone. Our research then explored the effects of periodic, positional perturbation in grating designs and found that at a 10-15% randomization factor, light extraction efficiency could improve up to 230% from the original top and bottom grating case. Next, in an experiment with PKU, we mounted a 2-fold symmetric photonic crystal onto a PDMS hemi-cylinder by nano-imprinting to measure the transmission of light at angles from near tangential to normal. Overall transmission of light compared with the non-grating design increases overall light extraction efficiency when integrated over the range of angles. Finally, our research focused on the 3-fold symmetric photonic crystal grating structure and employed the use of 3-D FDTD methods and incoherent light sources to better study the effects of higher-ordered symmetry in grating design. Grating cells were discovered as the source of escaping light from the GaN LED model. The model revealed that light extraction efficiency and the far-field diffraction pattern could be estimated by the position of grating cells in the grating design.

Radio frequency (RF) and microwave switches are widely used in several different applications including radar, measurement systems, telecommunications, and other areas. An RF switch can control a radar’s transmit vs. receive mode, select the operating band, or direct an RF signal to different paths. In this study, a single pole eight throw (SP8T) switch using only Surface Mount (SMT) components is designed and simulated in Keysight’s Advanced Design System (ADS). Single pole eight throw is defined as one input and eight possible outputs. A star network configuration with series-shunt PIN diode switches is used to create the 8-way RF switch. There are other commercially available SP8T switches from MACOM, Skyworks, Analog Devices, and other vendors that operate around this bandwidth. However, this design uses SMT components and series-shunt diode configurations to create a device in the GHz range and power handling in the high 20 to 30 dBm range. This study modeled components in ADS, including the PIN diodes and the bias tees. The project also analyzed multiple layouts, finalizing the optimal design to meet specifications. The insertion loss, bandwidth, isolation, return loss, power handling, and switching speed are analyzed in the final design. Key specifications for this design are determined by comparing to other commercially available SP4T and SP8T switches from MACOM, Skyworks, Analog Devices, and other vendors, as well as developing an operational switch over the 2-18 GHz bandwidth. Additional specifications include limiting insertion loss to 2.0 dB maximum and maximizing isolation to 30 dB minimum. Switching speed and power handling specifications are also set to 20 ns and 23 dBm, respectively. Future projects will work on design fabrication and improvements to the manufactured switch.