What Is Integrated Circuits: The Complete Guide

Are you looking for a faster way to transfer electricity? Integrated circuits are the best option as they work with different systems and gadgets, including smartphones, computers, medical equipment, and industrial machinery. These circuits come in various forms and are modified to meet specific needs and applications.

In this article we will teach you what integrated circuits are, their types, and how they work.

What Is an Integrated Circuit?

An integrated circuit is made of microelectronic circuits that are delicately assembled into one single fabricated unit. It is also known as chips or microchips and has miniaturized active devices such as diodes and transistors.

Integrated circuits are also made of passive devices, such as resistors and capacitors. Most devices often add these microscopic components since they are the best oscillators, amplifiers, and counter-logic gates.

While making integrated circuits, manufacturers also add delicate semiconductors such as silicon. These ICs come in different sizes and range from a few millimeters to a few square centimeters.

History of Integrated Circuits

The first attempt to make integrated circuits was in the 1920s when German engineers made a Loewe 3NF vacuum tube. Unlike the modern ICs, these vacuum tubes were designed to avoid tax while not sacrificing functionality.

In 1949, Werner Jacobi made an amplifying device with an integrated circuit-like semiconductor. However, this device did not receive immediate commercial use and was only used for manufacturing small and affordable hearing aids.

In 1957, Jack Kilby developed a Micromodule Program, which he pitched to the American Army. In July 1958, he developed a better design with all its components of electronic circuits completely integrated. He showcased a working example of his new design in September 1958. Because of his generous invention, he won a Nobel Prize in 2000.

Kibly’s invention was a hybrid integrated circuit chip with external wire connections, making it hard for manufacturers to mass-produce it. Months later, Robert Noyce invented a monolithic IC chip. Unlike Kilby’s chip, which used germanium, Noyce’s chip was made of silicone and used copper lines for connection.

In 1962, Steven Hofstein and Fred Heiman made an experimental MOS IC with 16 transistors. In 1964, General Microelectronics made a 120-transistor, which Robert Norman designed.

How Integrated Circuits Work?

Integrated circuits send and receive solid signals on the circuits they are attached to. They are made of many electronic components designed to perform a specific task.

For example, some components control power, send electric signals and receive data from other devices. Integrated circuits use silicone as their semiconductor material, and they are joined well so they can perform their tasks collectively.

Types of Integrated Circuits

There are different types of integrated circuits, and each type is designed for a specific application or use. They are classified according to their application, fabrication technology, and integration level. Here are different types of integrated circuits.

1. Based on Application

There are only two types of ICs under this category. They include:

Linear integrated circuits

They usually have an infinite number of continuous output and input states. They can be general-purpose, like the IC555, or special purpose, like the LM380, for audio amplification.

Digital integrated circuits

They are used to control defined signal amplitude levels. They also have a finite number of logic gates, flip-flops, multiplexers, and many other digital circuit components. Digital integrated circuits use binary input data, defining the data as 1 (high or true) and 0 (low or false).

These types are commonly used in microprocessors, computers, and digital signal processors. Different digital integrated circuits include memory chips, programmable circuits, and power management ICs.

2. Based on Technology

In this category, there are two types of ICs, which include monolithic technology and hybrid technology.

Monolithic Technology

Monolithic ICs such as the Operational amplifier IC741 are usually integrated into a single silicon semiconductor. These ICs come in two different forms such as:

  • Bipolar: ICs under this category are operated in saturation and are used as the main switch. The TTL is a good example of a bipolar-saturated family that is not driven into hard saturation.
  • Unipolar: ICs under this category use the MOS field, which affects transistors and is classified into three logic families. These families include the NMOS, PMOS, and CMOS. PMOS is the slowest and oldest, while NMOs are commonly used for large-scale integration (LSI). The CMOS uses the push-pull arrangement to operate but is preferred by people because it uses low power.

Hybrid technology

The hybrid technology uses a ceramic substrate that holds many silicon chips. It also uses mixed silicon chip technology along with GaA chips.

3. Based on the Integration Level

There are five types of Integrated Circuits in this category. They include:

  • Small-scale Integration: Can integrate to less than 100 devices
  • Mediums Scale Integration: Can integrate to 100 -10,000 devices
  • Large Scale Integration: Can integrate to 10,000 -1,000,000 devices
  • Very Large-scale Integration: Can integrate 1,000,000- 10,000,000 devices
  • Ultra Large-scale integration: Greater than 10,000,000

How are Integrated Circuits Manufactured?

The manufacturing process of these circuits is complex as it involves creating electronic components on a thin silicon substrate. Here are the steps that manufacturers follow when developing ICs.

Step 1: Wafer Preparation

This is the first step, where manufacturers cut, polish, and shape a thin slice of crystal silicon known as a wafer. These silicon crystals are pure and derived from a silicon melt in a boule.

Step 2: Oxidation

After preparing the wafer, it’s then passed through a high-temperature furnace for oxidation. When silicon is mixed with oxygen, a silicon oxide layer is formed on the surface of the integrated circuits. This layer acts as a mask or an insulator during other processing steps.

Depending on the type of ICs, manufacturers can decide to use water vapor or oxygen gas. Dry oxidation agents give better electrical properties, while wet oxidation is faster.

Step 3: Diffusion

This step involves introducing impurities on the highlighted areas of the wafer. These impurities are also known as dopants and help change the electrical characteristics of the IC. The wafer is passed in a furnace with dopant gas at this stage.

Here, the dopant atoms are diffused into the silicon openings available in the SiO2 layer. Remember, the dopants used can be P-type or N-type, depending on whether they donate or accept the electrons into the wafer.

Step 4: Ion Implantation

Here, the silicon wafer is doped with a beam of high-energy ions of their preferred dopant element. The ion implantation control is more precise than the diffusion process as it controls the dopant distribution and concentration better. However, this process causes more damage to the wafer, and the structure should be repaired through annealing.

Step 5: Chemical Vapor Deposition (CVD)

At this stage, a thin film of different materials forms on the silicon wafer. Some deposit materials used include silicon nitride, polysilicon, metal silicides, and metals like aluminum.

The CVD process involves exposing the wafer to the gas containing these elements. The gas reacts with the wafer’s surface, thus forming a solid coating.

Step 6: Photolithography

Photolithography involves photoresists transferring a pattern from a mask to the water’s surface. The mask formed can be negative or positive depending on whether it passes or blocks light through the openings.

The pattern layers formed can undergo further processing steps like doping, etching, or metallization.

Step 7: Metallization

This step involves the formation of metal interconnections between different layers of the integrated circuit. The most common metals deposited include copper and aluminum. They are deposited on the wafer surface through evaporation or CVD techniques.

After the metal layers are formed, they are patterned by etching and photolithography to create contact and wires that connect various components and terminals of the IC.

Step 8: Packaging

This is the last stage of integrated circuit formation and involves enclosing the IC chip in a casing. The protective casing also provides an electrical connection, mechanical support, and environmental protection.

The packaging is usually made of ceramic or plastic and comes in different shapes and sizes. Manufacturers also add leads and pins during this stage that help connect the integrated circuit to external devices.

Top Integrated Circuit Manufacturers in the Market

There are hundreds of IC manufacturers in the world. The most popular manufacturers include Infineon Technologies AG, Intel, Broadcom Inc, Qualcomm, Broadcom, Texas Instruments, Analog Devices (ADI), Nvidia, Samsung, and Micron Technology.


Most companies prefer using ICs as they enhance efficiency and increase the performance of devices. There are different types of integrated circuits, and each type is designed for a specific application or use. Remember, the availability of amplifiers and transistors on these ICs eases the overall process of sending signals and amplifying the final results.


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