This blog post explains in an easy-to-understand manner what semiconductors are and why they are important as the core of cutting-edge technologies such as Samsung Electronics, smartphones, and autonomous vehicles.
When people from non-science and engineering fields first hear the name “Department of Electrical Engineering,” they usually think of topics such as Samsung Electronics and semiconductors. In fact, the Department of Electrical Engineering covers a wide range of subjects beyond semiconductors, including power systems, electronic circuit design, communication systems, and control engineering, but the public often only hears news such as “Samsung Electronics’ semiconductor division’s highest operating profit ever” in the media. In this article, I will focus on semiconductors, which are of particular interest to the public, among the various fields covered by electrical engineering. I will explain what semiconductors are, how they are made, and the defects that can occur when they are manufactured and the need for research.
Many people have heard the word “semiconductor,” but few know its exact meaning. In general, everyone knows about conductors and non-conductors, but to put it simply, a conductor is an object that allows electricity to flow well, and a non-conductor is an object that allows electricity to flow very little. So what is a semiconductor? It is easy to misunderstand that it is a substance that allows electricity to flow “halfway,” as the word itself suggests. Semiconductors are usually made using silicon (Si) elements. Pure silicon is close to an insulator because it hardly allows any current to flow. However, the flow of current can be controlled by adding certain impurities to the silicon. This is done by adding impurities to the silicon atom structure so that “electrons” or “electron holes” are created, and the semiconductor has properties that are intermediate between those of a conductor and an insulator.
Why bother going through the complicated process of making semiconductors that do not allow electric currents to flow freely like conductors? It is because of the unique advantage of semiconductors that they can control the electrical conductivity. Electrical conductivity is a property that indicates how well an object allows electricity to flow, and it can be compared to the cross-sectional area of a waterway through which water flows. Just as the wider the waterway, the faster the water flows, the higher the electrical conductivity, the better the current flows. Semiconductors can freely adjust the width of this waterway, i.e. the electrical conductivity, by adjusting the type and amount of impurities. For example, there are p-type and n-type semiconductors. P-type semiconductors have holes (positive holes) that move with positive charges, while n-type semiconductors have electrons that move with negative charges. These two types of semiconductors can be combined to create basic devices such as diodes that control the flow of electric current.
Using these semiconductors, the most basic electronic component, the transistor, can be made. The transistor has the characteristic of opening and closing the path through which electric current flows, and thus it serves to amplify or switch electrical signals. Current technology allows the transistor to be made very small, on the order of tens of nanometers (nm). Billions of transistors are integrated into small devices such as smartphones to enable high-speed computing. Transistors are implemented in such a fine size and can efficiently control the flow of electrical signals, making them a key component of various electronic devices and computers.
However, various defects can occur in the semiconductor manufacturing process. This is a problem in which some of the billions of transistors do not work as intended, which greatly affects the reliability of semiconductor devices. In particular, a defect called a trap occurs in the semiconductor, which means that electrons are trapped in a “trap” and cannot move. A trap acts like a small hole in a waterway. If we try to pass a drop of water through the waterway at a constant rate, a hole in the middle of the waterway will prevent the water from flowing properly and interfere with the normal operation of the device. This will undermine the reliability of the electronic device and, in serious cases, may lead to a breakdown.
Reliability research is needed to solve the problems caused by traps. In electrical engineering, such research is being conducted to find the location and cause of the traps and develop technologies to reduce them in the manufacturing process. In particular, in this era where numerous electronic devices are pursuing high performance and miniaturization, reducing defects in semiconductors is a very important task.
As explained earlier about semiconductors, their manufacturing process, and defects, electrical engineering is not just about devices that allow current to flow, but also includes various research to improve the reliability of semiconductors, optimize the manufacturing process, and reduce defects. Semiconductors are small devices, but they are at the heart of modern technology, including smartphones, computers, home appliances, and automobiles, and their importance continues to grow. Recently, semiconductor technology has been in the spotlight as the foundation for the development of next-generation technologies such as autonomous vehicles, artificial intelligence, and the Internet of Things (IoT). Semiconductor research, which is advancing day by day, will make various technologies of the future possible.
Although this explanation is insufficient, I hope that readers will understand that the electronic devices they usually come into contact with are not just a combination of parts, but the product of precise processes and research for reliability and efficiency.
