Integrated Circuits – The Building Blocks of Electronics
Integrated circuits (IC) are the building blocks of modern electronic equipment. They put multiple functions — such as logic gates, RF and digital integrated circuits and microcontrollers — into a single chip.
ICs are used in all kinds of electronic devices. ICs are built from different circuit elements like capacitors, resistors and transistors.
Origins
Before the invention of the integrated circuit, electronic equipment consisted of a multitude of discrete components. This included transistors, diodes, resistors and capacitors. While these elements improved the functionality of electronics, they added to its size. It became imperative to miniaturize electronic circuits and reduce the number of soldered joints, lengths of connecting conductors and power consumption.
The first step to achieving this was the discovery of the transistor by William Shockley and his team at AT&T’s Bell Labs in 1947. This was a major breakthrough in the electronic industry, enabling smaller, more efficient devices. However, there was still a need to further improve the devices. They were still labor intensive and consumed a lot of materials.
Geoffrey Dummer was the first person to conceive of the idea of an integrated circuit in 1952. He believed that the more miniaturized a circuit was, the more reliable it would be. The invention of the integrated circuit allowed Dummer’s theory to come true.
A few years later in 1959, Jack Kilby was working at Texas Instruments. He was tasked with the job of developing a new technology called a “microcircuit.” On a warm July integrated circuit day, Kilby was at work and couldn’t take a vacation. This gave him a lot of time to think. That’s when he got the idea to combine multiple transistors and other circuit elements into one piece of semiconductor material.
Functions
Integrated circuits, or chips, are the fundamental building blocks of virtually all contemporary electronic devices. They contain millions of tiny active devices like transistors, diodes and capacitors etched on a wafer made from a semiconducting material, usually silicon. They perform many functions — including amplifying, controlling and generating electric signals — that once required a lot more bulky, individual components.
ICs can be categorized into three broad groups, depending on the nature of their intended functionality. Analog ICs work with continuous signals, such as direct voltages, and are used in applications such as audio amplifiers, temperature sensors and motor controllers. Digital ICs process electrical impulses that represent “1” or “0” using binary mathematics, and are essential to computer processing and memory. And radio frequency ICs, often referred to as “RF” ICs, work with wireless signals to transmit information and control devices like mobile phones.
Other types of ICs include memory chips, which store code and data as read-only or random-access memory, providing critical storage for the majority of modern electronic devices. Interface ICs manage communications for a variety of electronic devices and systems, increasing reliability and saving space by consolidating multiple functions into a single chip. And power management ICs help regulate and manage the flow of electricity, enabling manufacturers to shrink the size of their products while increasing performance.
Components
Integrated circuits, also referred to as microchips, consolidate myriad electronic constituents like transistors, resistors, diodes and capacitors onto a diminutive semiconductor foundation mainly composed of silicon. This consequential condensation significantly curtails the magnitude, heft and power utilization of electronic contrivances. ICs offer electronic component manufacturer distinct functionalities like signal amplification or complex digital calculations i.e. microprocessors.
ICs are comprised of several components like resistors, capacitors and transistors that perform a particular function like counting, timing and signal processing. In order to achieve the various functions of an IC, all these different components must be perfectly matched and fabricated on a single chip. Hence, a thorough understanding of the different components is necessary for an in-depth comprehension of integrated circuits.
Before the invention of ICs, traditional circuits were assembled using groups of wires and separate transistors, capacitors, and resistors, all of which were held together by soldered wires. The idea of integrating these individual elements into a single chip was first conceived in 1958 by Jack Kilby of Texas Instruments, Inc. and Robert Noyce of Fairchild Semiconductor Corporation independently of each other.
The IC is composed of a series of thin layers that are etched out on a wafer of pure silicon. Designers produce detailed drawings of exactly where the different electrical components should go on a chip. They then convert these drawings into photographic images that are reduced until they are the size of a chip. Several different layers of n-type and p-type semiconductor are then deposited on the wafer. Slender conductive threads then interlink all the different elements.
Manufacturing
The components of an integrated circuit are etched directly onto the surface of a chip made of a semiconductor, such as silicon. The chip may contain active devices, such as transistors, that amplify or control electric signals, and passive components such as resistors and capacitors, which store and resist electrical charges. The components are interconnected by metal wires, and all of the devices are microscopic in size. The entire circuit is called a monolithic integrated circuit, or IC, and it is often referred to as a microchip or microelectronic chip.
The manufacturing process begins with a computer-aided drafting machine that creates a pattern that will be transferred to the surface of the chip by an optical mask. The mask is opaque in some areas and clear in others, and it contains the images for many layers of circuits that will be formed on top of each other. Light waves in the visible range cannot be used because they would cause the circuits and chips to burn or melt. Instead, photons at higher frequencies are used to “expose” the various layers of material.
Carefully controlled amounts of impurities are added to the silicon, which is etched to form circuit elements such as transistors and wiring. The impurities are known as dopants, and they affect the way electric current moves through the chip. A dopant such as arsenic can be used to form a transistor that acts like a switch, turning current on and off as needed. The building-block approach to circuit design that is possible with ICs allows complex functions such as logic gates and precision amplifiers to be built. The resulting ICs are essential to modern technology, including computers and mobile phones, as well as digital memory chips.
