What are the advantages and disadvantages of different VLSI fabrication technologies?

All the computers existing since 1970 have used CMOS for their fabrication. While CMOS refers to a broad class of semiconductor technologies using complementary pairs of NMOS and PMOS transistors, FinFET is a specific transistor design within the CMOS framework. FinFETs provide enhanced performance and energy efficiency by adopting a three-dimensional structure, making them a crucial advancement in the evolution of semiconductor technology. Many modern CMOS processes, especially those at smaller technology nodes, use FinFET transistors to achieve higher levels of integration and improved performance.

Basic Components of CMOS Technology: Complementary Pair of Transistors: CMOS technology utilizes a complementary pair of metal-oxide-semiconductor field-effect transistors (MOSFETs): NMOS (N-type MOS) and PMOS (P-type MOS). NMOS transistors use n-type semiconductor material, while PMOS transistors use p-type semiconductor material. Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET): The fundamental building block of CMOS technology is the MOSFET, which consists of a metal gate, oxide insulator, and semiconductor material (either n-type or p-type). The gate voltage controls the flow of current between the source and drain terminals.

Imagine CMOS technology as a smart gadget that helps keep things running smoothly and efficiently. It’s like having a device that sips power rather than guzzling it, making it great for both tiny gadgets and big, powerful computers. CMOS is excellent at dealing with noise, which means it keeps things stable and reliable. However, it's not without its quirks. Making these gadgets can be pricey, and as they get smaller, they can start leaking power and picking up unwanted effects. Despite these challenges, CMOS is still a popular choice because it strikes a good balance between performance and power savings.

Imagine BiCMOS technology as a hybrid car combining the best features of two types of engines. On one side, you have bipolar transistors, which are like high-speed engines providing powerful performance and strong drive capabilities. On the other side, CMOS transistors act like fuel-efficient engines, offering low power use and high integration. By merging these two, BiCMOS chips excel in tasks needing both high performance and energy efficiency, such as in analog-to-digital converters or wireless communication devices. However, mixing these technologies can make the design and manufacturing process more complex and costly, and sometimes they don’t always play well together, which can pose compatibility issues.

Basic Components of BiCMOS Technology: Bipolar Junction Transistor (BJT): BiCMOS incorporates bipolar transistors alongside CMOS transistors. Bipolar transistors are known for their high-speed switching capabilities and low noise performance. Complementary Metal-Oxide-Semiconductor (CMOS): CMOS components, including both NMOS and PMOS transistors, are an integral part of BiCMOS technology. CMOS offers advantages such as low power consumption, high noise margins, and compatibility with digital applications. Integration of Bipolar and CMOS Components: BiCMOS allows for the integration of bipolar and CMOS components on the same chip.

VLSI technologies are one of the tools in a toolbox. CMOS is best for use in general, offering a mix of power efficiency and performance that makes it perfect to be included in everyday devices. But it is the other way round if you take account of BiCMOS; leveraging a combination logic functionality, CMOS provides high speed as well as Bipolar junction transistors combines both that have applications like wireless communications where they require high performance with reduced power consumption. Where GaAs is king of high-frequency like radar applications, SOI can actually enable faster and more efficient circuits by reducing parasitic effects.