Core of Integrated Circuits – CMOS Process Technology-Knowledge Encyclopedia-Shenzhen Kai Mo Rui Electronic Technology Co. LTD

Core of Integrated Circuits – CMOS Process Technology

Source：Shenzhen Kai Mo Rui Electronic Technology Co. LTD2026-08-08

CMOS, short for Complementary Metal-Oxide-Semiconductor, may sound complicated, yet it can be found in smartphones, computers, tablets and even smartwatches around us.

If the evolution of integrated circuit chips is regarded as the most gorgeous blossom in the history of humanity’s silicon civilization, CMOS technology has served as the fertile nourishment sustaining its vigorous growth over the past decades.

Without CMOS processes, there would be no modern integrated circuit (IC) manufacturing industry. People could not enjoy the convenience and fun brought by various electronic products, nor freely surf the Internet and mobile Internet. As the core manufacturing technology for modern IC chips, CMOS acts just like steel and concrete for constructing skyscrapers, delivering powerful "brains" and "hearts" for all electronic devices.

Basic Principles

CMOS (Complementary Metal-Oxide-Semiconductor) process technology lays the foundation of modern integrated circuit manufacturing and powers nearly all electronic equipment in daily life. It adopts two types of Field Effect Transistors (FETs), NMOS and PMOS, working complementarily to realize low-power and high-performance integrated circuits.

The MOSFET serves as the fundamental component of CMOS technology, categorized into P-type and N-type. Each MOSFET mainly consists of four parts: gate, source, drain and body.

Gate: Normally fabricated from polysilicon, stacked above a thin oxide layer (typically silicon dioxide, SiO₂).

Source and Drain: Composed of heavily doped semiconductors, placed on both sides of the gate.

P-type semiconductors are produced by doping trivalent elements (such as boron or gallium) into silicon. The outermost shell of trivalent atoms contains three electrons. When bonding with adjacent silicon atoms, a hole is formed. As other electrons fill this hole, the hole migrates and generates electric current.

N-type semiconductors are manufactured by doping pentavalent elements (such as phosphorus or arsenic) into silicon. Pentavalent atoms carry five outer-shell electrons; four form covalent bonds with neighboring silicon atoms, while the fifth electron is weakly bound to the atomic nucleus and easily becomes a free electron. The movement of free electrons creates electric current.

The operating principle of MOSFET relies on the electric field effect. When voltage is applied to the gate, an inversion layer forms in the semiconductor underneath the oxide layer, establishing a conductive channel between source and drain. The conductive channel can be turned on or off by adjusting gate voltage to control electric current.

The basic building block of a CMOS circuit is the inverter, formed by a series-connected P-type MOSFET and N-type MOSFET.

When input voltage is high level (Logic 1), the N-type MOSFET turns on and the P-type MOSFET turns off, resulting in low-level output (Logic 0).
When input voltage is low level (Logic 0), the P-type MOSFET turns on and the N-type MOSFET turns off, resulting in high-level output (Logic 1).

The advantage of this complementary architecture lies in static operation (constant input state): one of the two MOSFETs is always switched off, so the circuit consumes almost no DC current and achieves ultra-low power consumption.

Core Advantages of CMOS Process Technology

Low Power Consumption

CMOS circuits consume energy only during state switching with extremely low static power consumption, making them ideal for battery-powered devices.

High Integration Density

CMOS processes enable the fabrication of ultra-small transistors. Millions or even billions of transistors can be integrated onto a single chip to realize sophisticated functions.

Strong Noise Immunity

CMOS circuits are insensitive to noise interference, improving circuit reliability and stability.

Low Manufacturing Cost

The mature CMOS process supports mass production at scale and reduces the production cost of integrated circuits.

CMOS Process Technology Evolution

The development of CMOS processes continuously pursues smaller feature sizes, higher integration density and lower power consumption.

Photolithography

As one of the most critical technologies in CMOS manufacturing, the precision of photolithography directly determines feature size. From early contact photolithography and proximity photolithography to today’s Extreme Ultraviolet Lithography (EUV), the resolution of lithography systems keeps improving, enabling ultra-miniaturized feature sizes.

Multiple Patterning Technology

To break the resolution limits of single-exposure lithography, multiple patterning technology has been developed. It constructs complex patterns unachievable via single exposure through repeated exposure and etching, greatly enhancing lithography flexibility and precision.

High-k Metal Gate Technology

High-k metal gate technology is widely adopted to boost MOSFET performance and reduce leakage current. By using high dielectric constant materials and metals for gate stacks, gate capacitance is increased, and gate control over the channel is strengthened.

Application Scenarios

As the cornerstone of modern integrated circuit manufacturing, CMOS technology covers almost all electronic sectors and builds today’s well-known "digital world". Key application fields are listed below:

1. Digital Logic Circuits

Microprocessors (CPU): The "brain" of computers, smartphones and tablets, executing instructions and processing data.
Microcontrollers (MCU): Core components of embedded systems, widely used in home appliances, automotive electronics and industrial control.
Memory Chips: Including Dynamic Random Access Memory (DRAM) and Flash memory for data and program storage.
Digital Signal Processors (DSP): Chips dedicated to digital signal processing, deployed in audio, video and communication applications.

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