What is an Integrated Circuit?

An integrated circuit, also known as a microelectronic circuit or microchip, consists of a series of miniaturized active devices (transistors and diodes) and passive devices (resistors and capacitors) connected together on a semiconductor substrate. ICs can perform either analog or digital functions and are found in most electronic components.

ICs are typically labelled with a four-digit date code that indicates when the chip was manufactured. A number of ICs are combined on a small substrate, often ceramic, to form a multi-chip module.

Origins

The integrated circuit, also known as the IC or microprocessor, is a fundamental part of modern technology. It is used in computers, cell phones and a wide variety of electronic appliances. The IC is a semiconductor chip that contains electric components such as transistors, resistors and diodes. Its invention was a major milestone in the development of electronic technology and revolutionized the world of computing.

In the 1950s, engineers were looking for ways to make their products smaller. Transistors were already popular but they weren’t small enough for some new applications. A solution was needed to reduce the number of wires that connected the different parts of a circuit.

Geoffrey Dummer of the Royal Radar Establishment in the UK came up with an early concept for a device that would be later called an IC. His idea involved connecting multiple transistors with gold wires. But it never went commercially viable, mainly because the British military couldn’t find a use for it.

Jack Kilby of Texas Instruments and Robert Noyce of Fairchild both independently invented the integrated circuit integrated circuit around 1961. They didn’t know about each other’s work, and as a result, were both granted the first patent.

Advantages

The components of an integrated circuit are etched onto a piece of semiconducting material, such as silicon, so that they are close together. This makes the IC much smaller than individual component parts. It also consumes less power. The integrated circuit can be either analog or digital, or it may combine both types of signals in one chip.

Compared with separate, discrete circuits, ICs can have greater reliability and lower cost. This is because the non-recurring engineering (NRE) costs are spread over a larger production run, typically millions of units. Also, if any component fails, the rest of the circuit can still function. However, a problem with this type of circuitry is that changing the parameters of the integrated circuit requires rewiring it.

In the early stages of integration, called Small-Scale Integration or SSI, circuits contained transistors numbering in the tens. SSI was important for the Minuteman missile and Apollo program, which needed lightweight digital computers for their inertial guidance systems.

Today, integrated circuits can be found in every electronic device from a common wristwatch to a personal computer. They have revolutionized our world by making it possible to operate devices with a push of a button. For example, a microwave oven has an IC that sets the time to cook food. Researchers are even working on a chip that can be attached to the brain and used to repair different types of brain damage.

Applications

Integrated circuits can be classified into analog (used for audio amplification, voltage regulation and other functions) digital (used for microprocessors, memory chips and frequency counters) and mixed signal (both analog and digital on the same chip). They have replaced vacuum tubes in almost all electronic devices.

ICs are made of miniaturized active devices like transistors, which amplify or control an electric signal and passive components such as diodes and capacitors that store and resist electrical charges. These are built up on a wafer of semiconductor material, which is usually silicon. Using a process called “doping,” carefully controlled amounts of impurities are introduced into the silicon to affect its conductivity. This allows the circuits to function, and also makes it possible for other components to be incorporated into the chip.

The first ICs were large, but as technology improved the size of the circuits reduced and they became more affordable. They were initially used in aerospace applications such as the Minuteman missile and the Apollo program’s inertially guided flight computers.

Today, the IC is used in almost all electronic equipment from smartphones to washing machines. Its key contribution is that it significantly reduces the size of critical computer components and thus the overall size of IC integrated circuits devices containing them. Without the IC, there would not be slim smartphones or any of the other modern devices we use on a daily basis.

Manufacturing

Integrated circuits (also called microchips, microprocessors or ICs) are the brain and heart of most modern electronic devices. They perform various functions such as interpreting and executing program instructions or handling arithmetic operations on digital data. They are found in computers, cell phones, cameras, televisions, microwave ovens and even household electronics like electric toothbrushes and cars.

The manufacturing process starts with a detailed circuit schematic. This is then converted to a mask layout for fabrication. This step can take up to six weeks and is performed in highly specialized semiconductor fabrication plants, also known as “foundries” or “fabs”.

Each layer of the final chip is defined by photolithography, with different color layers denoting where areas of n-type or p-type dopants are added to the substrate. Other layers define the conductors themselves, which may be doped polysilicon or metal. Finally, a layer of passivation is added to seal the wafer from water and other contaminants. Holes are etched through this layer in certain locations to make the necessary connections for each circuit element.

The resulting integrated circuits can be made up of transistors, diodes and resistors or more complex blocks such as logic gates or precision amplifiers. They can even contain the entire microprocessor that makes up the central processing unit of a computer or the memory devices that store digital information.