Integrated Circuits/Microchips

With the world marching inexorably towards the fourth industrial revolution (IR 4.0), one is now embracing lives with artificial intelligence (AI), the Internet of Things (IoTs), virtual reality (VR) and 5G technology. Wherever we are, whatever we are doing, there are electronic devices that we rely indispensably on. While some of these technologies, such as those fueled with smart, autonomous systems, are seemingly precocious; others have existed for quite a while. These devices range from simple home appliances, entertainment media to complex aeronautical instruments. Clearly, the daily lives of mankind today are interwoven seamlessly with electronics. Surprising as it may seem, the cornerstone that empowers these electronic devices is nothing more than a mere diminutive semiconductor cube block. More colloquially referred to as the Very-Large-Scale-Integration (VLSI) chip or an integrated circuit (IC) chip or simply a microchip, this semiconductor cube block, approximately the size of a grain of rice, is composed of millions to billions of transistors. The transistors are interconnected in such a way that allows electrical circuitries for certain applications to be realized. Some of these chips serve specific permanent applications and are known as Application Specific Integrated Circuits (ASICS); while, others are computing processors which could be programmed for diverse applications. The computer processor, together with its supporting hardware and user interfaces, is known as an embedded system.In this book, a variety of topics related to microchips are extensively illustrated. The topics encompass the physics of the microchip device, as well as its design methods and applications

Rf Power Amplifier And Oscillator Design For Reliability And Variability

CMOS RF circuit design has been an ever-lasting research field. It gained so much attention since RF circuits have high mobility and wide band efficiency, while CMOS technology has the advantage of low cost and better capability of integration. At the same time, IC circuits never stopped scaling down for the recent many decades. Reliability issues with RF circuits have become more and more severe with device scaling down: reliability effects such as gate oxide break down, hot carrier injection, negative bias temperature instability, have been amplified as the device size shrinks. Process variability issues also become more predominant as the feature size decreases. With these insights provided, reliability and variability evaluations on typical RF circuits and possible compensation techniques are highly desirable. In this work, a class E power amplifier is designed and laid out using TSMC 0.18 µm RF technology and the chip was fabricated. Oxide stress and hot electron tests were carried out at elevated supply voltage, fresh measurement results were compared with different stress conditions after 10 hours. Test results matched very well with mixed mode circuit simulations, proved that hot carrier effects degrades PA performances like output power, power efficiency, etc. Self- heating effects were examined on a class AB power amplifier since PA has high power operations. Device temperature simulation was done both in DC and mixed mode level. Different gate biasing techniques were analyzed and their abilities to compensate output power were compared. A simple gate biasing circuit turned out to be efficient to compensate selfheating effects under different localized heating situations. iv Process variation was studied on a classic Colpitts oscillator using Monte-Carlo simulation. Phase noise was examined since it is a key parameter in oscillator. Phase noise was modeled using analytical equations and supported by good match between MATLAB results and ADS simulation. An adaptive body biasing circuit was proposed to eliminate process variation. Results from probability density function simulation demonstrated its capability to relieve process variation on phase noise. Standard deviation of phase noise with adaptive body bias is much less than the one without compensation. Finally, a robust, adaptive design technique using PLL as on-chip sensor to reduce Process, Voltage, Temperature (P.V.T.) variations and other aging effects on RF PA was evaluated. The frequency and phase of ring oscillator need to be adjusted to follow the frequency and phase of input in PLL no matter how the working condition varies. As a result, the control signal of ring oscillator has to fluctuate according to the working condition, reflecting the P.V.T changes. RF circuits suffer from similar P.V.T. variations. The control signal of PLL is introduced to RF circuits and converted to the adaptive tuning voltage for substrate bias. Simulation results illustrate that the PA output power under different variations is more flat than the one with no compensation. Analytical equations show good support to what has been observed

A Flexible, Highly Integrated, Low Power pH Readout

Medical devices are widely employed in everyday life as wearable and implantable technologies make more and more technological breakthroughs. Implantable biosensors can be implanted into the human body for monitoring of relevant physiological parameters, such as pH value, glucose, lactate, CO2 [carbon dioxide], etc. For these applications the implantable unit needs a whole functional set of blocks such as micro- or nano-sensors, sensor signal processing and data generation units, wireless data transmitters etc., which require a well-designed implantable unit.Microelectronics technology with biosensors has caused more and more interest from both academic and industrial areas. With the advancement of microelectronics and microfabrication, it makes possible to fabricate a complete solution on an integrated chip with miniaturized size and low power consumption.This work presents a monolithic pH measurement system with power conditioning system for supply power derived from harvested energy. The proposed system includes a low-power, high linearity pH readout circuits with wide pH values (0-14) and a power conditioning unit based on low drop-out (LDO) voltage regulator. The readout circuit provides square-wave output with frequency being highly linear corresponding to the input pH values. To overcome the process variations, a simple calibration method is employed in the design which makes the output frequency stay constant over process, supply voltage and temperature variations. The prototype circuit is designed and fabricated in a standard 0.13-μm [micro-meter] CMOS process and shows good linearity to cover the entire pH value range from 0-14 while the voltage regulator provides a stable supply voltage for the system

Energy autonomous systems : future trends in devices, technology, and systems

The rapid evolution of electronic devices since the beginning of the nanoelectronics era has brought about exceptional computational power in an ever shrinking system footprint. This has enabled among others the wealth of nomadic battery powered wireless systems (smart phones, mp3 players, GPS, …) that society currently enjoys. Emerging integration technologies enabling even smaller volumes and the associated increased functional density may bring about a new revolution in systems targeting wearable healthcare, wellness, lifestyle and industrial monitoring applications

Floating-Gate Design and Linearization for Reconfigurable Analog Signal Processing

Analog and mixed-signal integrated circuits have found a place in modern electronics design as a viable alternative to digital pre-processing. With metrics that boast high accuracy and low power consumption, analog pre-processing has opened the door to low-power state-monitoring systems when it is utilized in place of a power-hungry digital signal-processing stage. However, the complicated design process required by analog and mixed-signal systems has been a barrier to broader applications. The implementation of floating-gate transistors has begun to pave the way for a more reasonable approach to analog design. Floating-gate technology has widespread use in the digital domain. Analog and mixed-signal use of floating-gate transistors has only become a rising field of study in recent years. Analog floating gates allow for low-power implementation of mixed-signal systems, such as the field-programmable analog array, while simultaneously opening the door to complex signal-processing techniques. The field-programmable analog array, which leverages floating-gate technologies, is demonstrated as a reliable replacement to signal-processing tasks previously only solved by custom design. Living in an analog world demands the constant use and refinement of analog signal processing for the purpose of interfacing with digital systems. This work offers a comprehensive look at utilizing floating-gate transistors as the core element for analog signal-processing tasks. This work demonstrates the floating gate\u27s merit in large reconfigurable array-driven systems and in smaller-scale implementations, such as linearization techniques for oscillators and analog-to-digital converters. A study on analog floating-gate reliability is complemented with a temperature compensation scheme for implementing these systems in ever-changing, realistic environments

Fault and Defect Tolerant Computer Architectures: Reliable Computing With Unreliable Devices

This research addresses design of a reliable computer from unreliable device technologies. A system architecture is developed for a fault and defect tolerant (FDT) computer. Trade-offs between different techniques are studied and yield and hardware cost models are developed. Fault and defect tolerant designs are created for the processor and the cache memory. Simulation results for the content-addressable memory (CAM)-based cache show 90% yield with device failure probabilities of 3 x 10(-6), three orders of magnitude better than non fault tolerant caches of the same size. The entire processor achieves 70% yield with device failure probabilities exceeding 10(-6). The required hardware redundancy is approximately 15 times that of a non-fault tolerant design. While larger than current FT designs, this architecture allows the use of devices much more likely to fail than silicon CMOS. As part of model development, an improved model is derived for NAND Multiplexing. The model is the first accurate model for small and medium amounts of redundancy. Previous models are extended to account for dependence between the inputs and produce more accurate results

Advances in Solid State Circuit Technologies

This book brings together contributions from experts in the fields to describe the current status of important topics in solid-state circuit technologies. It consists of 20 chapters which are grouped under the following categories: general information, circuits and devices, materials, and characterization techniques. These chapters have been written by renowned experts in the respective fields making this book valuable to the integrated circuits and materials science communities. It is intended for a diverse readership including electrical engineers and material scientists in the industry and academic institutions. Readers will be able to familiarize themselves with the latest technologies in the various fields

Charge pumps and floating gate devices for switching applications

On-chip impedance tuning is used to overcome IC perturbations caused by packaging stress. Tuning is more important for matching networks of radio frequency (RF) systems. Possible package resonance and fabrication process variations may cause instability, which is a major problem in RF systems. Thus, precautions need to be taken in order to maintain the overall stability of components and the final system itself. Electrically erasable programmable read-only memory switches (EEPROMs) occupy less die area compared to e-fuses and microelectromechanical system (MEMS) switches, thus EEPROMs are proposed to be used as tuning switches in millimetre-wave (mm-wave) applications. It is anticipated that EEPROM switches will also enable multi-time programming because of the smaller area and the fact that more switches can be used for fine-tuning. The problem addressed in this research is how suitable EEPROMs are for switching applications in the mm-wave region. The main focus of this dissertation is to characterise the suitability of EEPROM switches qualitatively for tuning with systems operating in the mm-wave spectrum. 130 nm SiGe BiCMOS IBM 8HP process technology was used for simulation and the fabricated prototypes. The Dickson charge pump (CP), two voltage doubler CPs and four floating gate (FG) devices were investigated. Literature and theoretical verification was done using computer aided design (CAD) Cadence software through circuit analysis and the layouts were also designed for integrated circuit (IC) prototype fabrication. The qualitative evaluation of the hypothesis was based on investigating reliability issues, switching characteristics, CP output drive capability and mm-wave characterisation. The maximum measured drain current for FGs was 1.4 mA, 2.7 mA and 3 mA for devices 2, 3 and 4, respectively. The ratio between ON state switching current (after tunnelling) and OFF state switching current (after injection) was 1.5, 1.35 and 6 for devices 2, 3 and 4, respectively. The ratios correlated with the expected results in terms of FG transistor area: a high area results in a higher ratio. Despite the correlation, devices 2 and 3 may be unsuitable because the ratio is less than 2: a smaller ratio between the ON and OFF states could also result in higher losses. The Dickson CP achieved an output voltage of 2.96 V from an input of 1.2 V compared to 3.08 V as computed from the theoretical analysis and 4.5 V from the simulation results. The prototypes of the voltage doubler CP did not perform as expected: a maximum of 1 V was achieved compared to 4.1 – 5 V as in the simulation results. The suitability of FG devices for switching applications depends on the ratio of the ON and OFF states (associated to insertion and isolation losses): the larger the FG transistor area, the higher the ratio. The reliability issues are dominated by the oxide thickness of the transistor, which contributes to charge leakages and charge trapping: smaller transistor length causes more uncertainties. Charge trapping in the oxide increases the probability of leakages and substrate conduction, thus introduces more losses. Based on the findings of this research work, the FG devices promise to be suitable for mm-wave switching applications and there is a need for further research investigation to characterise the devices in the mm-wave region fully. AFRIKAANS : Impedansie-instelling op skyf word gebruik om steurings in geïntegreerde stroombane wat deur verpakkingstres veroorsaak word, te oorkom. Instelling is meer belangrik om netwerke van radiofrekwensiesisteme te paar. Moontlike verpakkingresonansie en variasies in die vervaardigingsproses kan onstabiliteit veroorsaak, wat ‟n groot probleem is in radiofrekwensiesisteme. Voorsorg moet dus getref word om die oorhoofse stabiliteit van komponente en die finale sisteem self te handhaaf. Elektries uitveebare programmeerbare slegs-lees-geheueskakelaars (EEPROMs) neem minder matrysarea op as e-sekerings en die sekerings van mikro-elektromeganiese sisteme en word dus voorgestel vir gebruik as instellingskakelaars in millimetergolfaanwendings. Daar word verwag dat EEPROM-skakelaars ook multi-tydprogrammering sal moontlik maak as gevolg van die kleiner area en die feit dat meer skakelaars gebruik kan word vir fyn instellings. Die probleem wat in hierdie navorsing aandag geniet, is die geskiktheid van EEPROMS vir skakelaanwendings in die millimetergolfstreek. The hooffokus van die verhandeling is om die geskiktheid van EEPROM-skakelaars kwalitatief te karakteriseer vir instelling met sisteme wat in die millimetergolfspektrum funksioneer. Department of Electrical, Electronic and Computer Engineering v University of Pretoria 130 nm SiGe BiCMOS IBM 8HP-prosestegnologie is gebruik vir simulasie en die vervaardigde prototipes. Die Dickson-laaipomp is gebruik vir simulasie en die vervaardigde prototipes. Die Dickson-laaipomp, twee spanningverdubbelinglaaipompe en vier swewendehektoestelle is ondersoek. Literatuur- en teoretiese verifikasie is gedoen met behulp van rekenaarondersteunde-ontwerp (CAD) Cadence-sagteware deur stroombaananalise en die uitleg is ook ontwerp vir die vervaardiging van geïntegreerdestroombaanprototipes. Die kwalitatiewe evaluasie van die hipotese is gebaseer op die ondersoek van betroubaarheidkwessies, skakelingeienskappe, laaipompuitsetdryfvermoë en millimetergolfkarakterisering. Die maksimum gemete dreineerstroom vir swewende hekke was 1.4 mA, 2.7 mA en 3 mA vir onderskeidelik toestelle 2, 3 en 4. Die verhouding tussen die AAN-toestand van die skakelstroom (na tonnelling) en die AF-toestand van die skakelstroom (na inspuiting) was 1.5, 1.35 en 6 vir toestelle 2, 3 en 4, onderskeidelik. Die verhoudings het ooreengestem met die verwagte resultate rakende die swewendehek-transistorareas: ‟n groot area het ‟n hoër verhouding tot gevolg. Nieteenstaande die ooreenstemming, mag toestelle 2 en 3 moontlik nie geskik wees nie, omdat die verhouding kleiner as 2 is: ‟n kleiner verhouding tussen die AAN- en AF-toestande mag ook hoër verliese tot gevolg hê. Die Dickson-laaipomp het ‟n uitsetspanning van 2.96 V vanaf ‟n inset van 1.2 V vergeleke met 3.08 V soos bereken volgens die teoretiese analise en 4.5 V volgens die simulasieresultate. Die prototipes van die spanningverdubbelinglaaipomp het nie gefunksioneer soos verwag is nie: ‟n maksimum van 1 V is bereik vergeleke met 4.1 – 5 V soos in die simulasieresultate. Die geskiktheid van swewendehektoestelle vir skakelingtoepassings hang af van die verhouding van die AAN- en AF-toestande (wat met invoer-en isolasieverlies geassosieer word): hoe groter die swewendehektransistorarea, hoe hoër die verhouding. Die betroubaarheidkwessies word oorheers deur die oksieddikte van die transistor, wat bydra tot ladinglekkasies en ladingvasvangs: korter transistorlengte veroorsaak meer onsekerheid. Ladingvasvangs in die oksied verhoog die moontlikheid van lekkasies en substraatgeleiding en veroorsaak dus groter verlies. Die bevindings van hierdie navorsing toon dat swewendehektoestelle waarskynlik geskik is vir millimetergolfaanwendings en verdere navorsing is nodig om die toestelle volledig in die millimetergolfstreek te karakteriseer. CopyrightDissertation (MEng)--University of Pretoria, 2013.Electrical, Electronic and Computer Engineeringunrestricte