Epitaxy 101

Our core business is "Epitaxy"

IQE's core business is the design and manufacture of compound semiconductor wafers or "epiwafers" using a process called epitaxy.

Epitaxy is the process of growing structures in a specific crystalline orientation on top of another crystalline layer or substrate, where the orientation is determined by the underlying crystal.

 The word epitaxy derives from the Greek prefix epi meaning “upon” and taxis meaning “arrangement” or “order.” The atoms in an epitaxial layer have a specific registry relative to the underlying crystal. 

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These epitaxial layers uniquely define the wireless, photonic and electronic performance of our epiwafers which are then processed by our customers to produce the "chips" that are found in virtually all of today's technology devices and gadgets.


Without the compound semiconductor wafers that IQE produce, there would be no smartphones, high speed internet, satellite navigation or WiFi.

What is epitaxy? 

Epitaxy is the first stage in the process of manufacturing the critical components in a wide range of devices from mobile handsets to solar cells and LEDs, and it requires high specification cleanrooms, sophisticated production tools and high levels of intellectual property.

IQE produces atomically engineered layers of crystalline materials containing a variety of semiconductor materials such as gallium, arsenic, aluminium, indium and phosphorous.

An epiwafer can include hundreds of individual layers, each of which may be as thin as two or three atoms.

IQE's intellectual property (IP) or know-how is the science  and technology behind the materials and the way in which the atomic structures can be manufactured to yield the wide range of electronic, photonic and electronic properties that are essential in today's electronically enabled age.

The elements  

The periodic table, first published in 1869 by Dmitri Mendeleev, shows the 118 currently known chemical elements arranged in eight groups according to their properties.

Of particular interest in electronics and photonics is the fact that the elements up to and including those in group III are in general, known as metals and tend to be good conductors of electricity, whilst those from group V and above are generally non-metals and tend to be poor conductors of electricity.

Between the metals and non-metals, those in group IV are elements whose electrical properties are somewhere between conducting and non-conducting (insulating). These elements, which include silicon and germanium, are known as semiconductors.   

The behaviour of semiconducting elements was discovered during the 19th century and it later became known through experimentation that their electrical properties could be altered by adding very small amounts of different impurities and that by placing together two pieces of material with different impurities, an electrical current could be controlled by allowing it to flow in one direction but not the other.

 

The semiconductor age is born

It was in 1947 that William Shockley, John Bardeen and Walter Brattain, working at Bell Labs, built the World’s first transistor using the element germanium. 

During the two decades that followed, the ability to control electrical currents using semiconductors allowed engineers to develop a range of new electronic technologies.

The evolution of silicon

Whilst germanium is a very efficient semiconductor material, the ready availability of silicon made for a compelling low-cost alternative and hence a new industry was born that has, for the last five-decades, transformed our lives in so many ways.

Silicon has been the backbone of the electronics revolution from the 1960s, largely by virtue of continuous miniaturisation which has led to an exponential increase in technological performance - a concept notably observed by one of the founders of Intel, Gordon Moore, and known as “Moore’s Law”.

Introducing compound semiconductors

Impressive as the impact of silicon has been on our lives, being a single element, it has a very basic and limited set of properties that restricts its application in many new and emerging technology areas that demand ultra-high performance levels along with sensing and other capabilities. 

By atomically engineering crystal structures that combine elements either side of those in group IV of the periodic table (e.g. groups III and V), a set of new semiconductor materials has emerged whose enhanced properties offer significant capability and performance improvements over those of silicon alone. 

Compound semiconductors provide significant performance advantages that are absolutely essential for a growing range of technology applications. In general terms, these advantages fall into three categories: speed, light and power.

SPEED - Compound semiconductors such as GaAs and InP can operate at speeds that are several orders of magnitudes higher than is possible using silicon alone. 

LIGHT – Unlike silicon, compound semiconductors can generate and receive a broad range of the electromagnetic spectrum from high frequency ultraviolet through the visible spectrum to long wavelength infrared light.

POWER – Compound semiconductors including silicon carbide (SiC) and GaN are capable of operating at high powers (high voltages and current levels) and are highly efficient at converting different types of power and at high frequencies.

Today, Semiconductors in the form of both silicon and compound semiconductors, form the heart of many technology applications that have an everyday impact on the way we live, work and spend our leisure time. Without semiconductors, many devices and applications that we rely on simply would not exist.

Semiconductors are a key enabling technology that feed into multiple supply chains feeding a wide range of market sectors including: communications and connected devices (5G), healthcare technologies, electrically powered connected autonomous vehicles, aerospace technologies, safety & security systems, efficient energy generation and consumption, robotics and AI.

Compound semiconductors have already complimented silicon in areas such as wireless communications, where chips made from material combinations such as gallium and arsenic (gallium arsenide, or GaAs) are found in virtually every smartphone where they enable high speed, high efficiency wireless communications in cellular and WiFi networks.

Other properties offered by compound semiconductor materials include the ability to emit and sense light in the form of general lighting (LEDs) and communications (lasers and receivers for fibre-optics). 

The photonic and power efficiency properties offered by compound semiconductors that could not be achieved with silicon alone, will enable technologies essential in areas such as safety and security systems, healthcare technologies, aerospace and automotive applications including electrically powered and autonomous vehicles.

It is our ability to harness the advanced properties of the full range of semiconducting materials that will drive the digital revolution for generations to come. Welcome to the world of advanced, compound semiconductors. Compound semiconductors are the DNA of next generation technologies.

IQE’s Epiwafers

IQE manufactures compound semiconductor material in the form of a wafer or "epiwafer" by growing complex atomic structures on the surface of a substrate (a disc of pure crystalline material) using a process called epitaxy.

Epitaxial growth is a process whereby complex atomic structures are produced under precisely controlled conditions. The end product is a pure, crystalline, semiconductor wafer upon which complex structures comprising many individual atomic layers have been grown.

These epitaxial layers uniquely define the wireless, photonic and electronic performance of our epiwafers which are then processed by our customers to produce the "chips" that are found in virtually all of today's technology devices and gadgets.

Epitaxy is the first key stage in the process of manufacturing the critical components in a wide range of devices from mobile handsets to solar cells, lasers and LEDs, and it requires high specification cleanrooms, sophisticated production tools and high levels of process knowhow and intellectual property.

IQE produces atomically engineered layers of crystalline materials containing a variety of semiconductor materials such as gallium, arsenic, aluminium, indium and phosphorous. The layers are grown onto a crystal substrate or wafer and the finished product containing the wafer and its atomically modified surface is known as an epiwafer. It is the number of layers, their atomic composition and the order in which they are grown that determines the precise physical, electronic and optical properties of the material. An epiwafer can include hundreds of individual layers, each of which may be as thin as two or three atoms.

IQE's IP and process know-how is the science  and technology behind the materials and the way in which the atomic structures can be manufactured to yield the wide range of wireless, photonic and electronic properties that are essential in today's electronically enabled age.