STUDY Introduction to advanced VLSI Design
- 1. 1 Why Integrated Circuit? Limitation of Discrete circuits: 1. Assembling and wiring of all individual discrete components take more time and occupies a larger space required. 2. Designing the Circuitry –more area and high power consumption 3. Replacement of a failed component is complicated 4. Less reliability - elements are connected using soldering process 5. To overcome these problems, integrated circuits are developed. IC has millions of electronic components, like transistors, resistors, and capacitors, constructed into a single unit. Today almost every electronic device (computers, cell phones, cars, televisions, digital watches) use ICs due to its small size and high reliability and efficiency.
- 2. 2 1. VLSI System Design 2. VLSI Circuit or Processor Design 3. VLSI Physical Layout & Chip VHDL Verilog SystemC Matlab Synopsys Cadence Mentor Graphics Tanner MultiSim PSCAD Silva co EDA Tools Historical Perspective of ICs
- 3. SYSTEM–RELATED Partitioning into cabinets, boards, and circuits Mixed digital and analog circuits on the same chip and I/O interface System Clock frequencies and Power dissipation CIRCUIT–RELATED Internal Data transfer frequencies and Interconnection Non critical timing paths and Drive capacity for internal buffers Process technology……….Circuit area, yield, and packaging External Propagation delay…… I/O Compatibility Loads that have to be driven………. Drive capacity for output buffers DESIGN-EFFORT-RELATED CAD tools and Layout style ……..Module generators and Cell library Regularity and modularity of the device Clusters General Challenges High density: Reduced feature size: 0.25µm -> 0.16 µm…….% of wire/routing area^ Low power/high speed: Decreased operating voltage: 1.8V -> 1V Increased clock frequency: 500 MHz-> 1GH. High complexity: Increased transistor count: 10M transistors and higher Shortened time-to-market delay: 6-12 months VLSI Design Issues
- 4. 4 Low-Power Design Techniques Architectural design Logic design Circuit design Physical design Fabrication Input-Output Memory Data Path Control Unit 1. System: Partitioning, Power down 2. Algorithm: Complexity, Concurrency, Regularity 3. Architecture: Parallelism, Pipelining, Redundancy, Data Encoding 4. Circuit Logic: Logic Styles, Energy Recovery, Transistor Sizing 5. Technology: Threshold Reduction, Multi-threshold Devices.
- 5. FPGA tool flow 5 Figure: HLS tools produce HDL which allows register-transfer (RT) synthesis into a digital circuit, finally deployed on an FPGA. (Source: Greg S. via University of Florida Slides;)
- 6. FPGA Controller for PEM-FC Systems Fuel Cell Stack DC DC DC AC Filter Grid vga vgb vgc iga igb igc Amp PI Controller Modified SRF controller Hysteresis current controller PWM generator IDC Load FPGA Processor VDC Design and Development of an FPGA Controller for PEM Fuel Cell Power Systems Sponsored by DAE, BRNS; San. No. 34/14/53/2014- BRNS dated 12/12/2014
- 7. 7 Tentative Research Proposal Design an energy efficient SRAM circuit using leakage current control techniques Due to scaling of Vt and VDD -> exponential increases in leakage currents in standby mode and dynamic mode of operation. In SRAM cell, three type of leakage current such as sub-threshold current, gate leakage current and junction leakage current. Based on the issues, the objective of the research is framed as Design sub-micron SRAM cell for today’s system-on-chip and high performance portable devices. Develop a suitable leakage control techniques and to propose novel structure without regretting the functionality of SRAM. To increase robust in scalable devices without compromise the unique function of read and write, data retain of the SRAM cells. Analysis trade-off between power and performance.
- 8. 8 Overview of Wafer Preparation
- 9. Why Silicon? Silicon is abundant in the earth in the form of quartzite and low cost Other reason: This allows gap MOSFET to be more easily made as the SiO2 forms the insulating layer for the Gate, Protects and passivates underlying circuitry helps in patterning and useful for dopant masking. Si has a very nice bandgap of ~ 1.12 eV relatively high dielectric strength ->suitable for power devices. Stable and strong material & crystal structure like diamond Higher operating temperature (125-175ºC vs. ~85 ºC) Large variety of process steps possible without the problem of decomposition (as in the case of compound semiconductors) Electric resistivity : (20 °C) 103 Ω·m Thermal conductivity: (300 K) 149 W·m−1 ·K−1
- 10. 10 1. Silicon Wafer Manufacturing 1. Czochralski Method (CZ) 2. Float Zone Method 3. Bridgman Method 2. Epitaxial Deposition Techniques 1. Vapour Phase Epitaxial (VPE) or Chemical Vapor Deposition 2. Molecular Beam Epitaxial (MBE) 3. Liquid Phase Epitaxial (LPE) 3. Technique of oxidation 1. Thermal Oxidation 2. Wet Oxidation 3. Dry Oxidation 4. Steam Oxidation-> Vapor Phase Technique (CVD) 5. Plasma Oxidation 6. Anodization 7. High Pressure Oxidation
- 11. 11 4. Lithography 1. Photolithography 2. Electron Beam Lithography 3. Extreme ultraviolet : EUV 4. X-ray Lithography 5. Etching 1. Wet Chemical / Wet Etching 2. Dry Etching 1. Non-plasma Etching /Plasma Etching 2. Sputtering Etching / Ion Milling 3. Reactive Ion Etching (RIE) – processes 6. Diffusion system based on Source 1. Solid / Liquid / Gaseous source diffusion system 2. Spin-on diffusion system 7. Ion implantation system 8. Methods of Metallization 1. Electrochemical Plating or Polishing 2. PVD – Evaporation & Sputtering 3. CVD
- 12. 12 With basic components like resistor, diode, and transistor a basic circuit is configured and fabricated to its monolithic form. Discrete to Integrated Circuit Basic monolithic IC Circuit Basic monolithic IC Cross-Sectional View Resistor- ohmic value by concentration of doping impurity and depth of diffusion Capacitor: (1) All P-N junctions have capacitance. (2) One plate is formed by diffusing a heavily doped N-region and other plate is formed by depositing a film of aluminium on the silicon dioxide. (3) Using the silicon dioxide as a dielectric may also be a way to fabricate. Diode - fabricated by the same diffusion process as transistors are. The only difference is that only two of the regions are used to form one P-N junction
- 13. VLSI Emerging Technologies -Changing the World 1. AI and Robotics -> AI is being able to endow a robot with human intellectual . The robot or computer would be able to learn anything, speak a language, Capacity to reason and give original ideas just like humans. 2. Augmented Reality(AR) -> Neurochemistry behind our Sensory experiences in real World. The AR interactive is Virtual-based display environment that takes the capabilities of computer generated Sound, Text, Graphics and Effects to enhance the user's real-world experience. AR GPS Drive/Walk Navigation 3. Micro-electro-mechanical Systems (MEMs) -> Micro-computers with extremely small mechanical features such as Gears, Valves, Actuators and Pumps. The MEMs based Medical care chips can do a lot to monitor and check patient body system. 4. Nano-materials -> This technology is applied in health care (such as diagnostics, regenerative medicine, and drug delivery), Textiles, Environmental Protection, Cosmetics, and Electronics 5. Entertainment – TVs, Movies, Sports and Events 6. IT and Communication Technology 7. Medical – Artificial Body Implants 8. Transport and Security– Space elevator, Space- plane Flying car
- 14. 1st Industrial Revolution (1780s): The Age of Mechanical Equipment STEAM engine, steam was powering everything from agriculture to textile manufacturing. WATER, Mechanical Production Equipment 2nd Industrial Revolution (1870s): Age of Science & Mass Production Things started with a number of key inventions. Gasoline engines, Electricity, Airplanes, Chemical fertilizer. 3rd Industrial Revolution(1970s): The Digital Revolution Semiconductors, Mainframe computing, Personal computing, and the Internet—the digital revolution; Electronics, IT and Automated Production 4th Industrial Revolution: Starting Now! Industrial Revolution