The heat generated by semiconductor chips can degrade the performance and lifespan of devices, and to reduce it, scientists are introducing new materials and design approaches. In particular, innovative technologies such as double-gate and front-gate transistors are emerging as important solutions to reduce heat generation.
Ten minutes into a call with your phone to your ear, your ear is hot from the phone’s heat. Most of the heat in electronics comes from the semiconductor chips at the heart of the device. The heat generated by semiconductor chips has already exceeded 100W/㎠. This means that a chip the size of your fingernail is hotter than a 100W light bulb in the palm of your hand. This heat doesn’t just cause discomfort to the user, it also affects the performance of the device itself. This has made thermal management a critical issue in smartphones, computers, and other electronics. By 2010, experts estimate that a chip the size of a fingernail will generate 1000 W/cm2 of heat. So what is the relationship between semiconductor chips and heat?
A semiconductor chip is a circuit with a large number of transistors integrated into it. A transistor is composed of three electrodes (source, gate, and drain), and under certain conditions, the gate allows current to flow from the source to the drain, or breaks it, allowing the transistor to perform logical operations. This process consumes power and generates heat. Semiconductor chip technology has evolved by shrinking the size of devices and increasing their density. Integration is the number of transistors per unit area. By shrinking the size of transistors to fit more transistors on a chip, the pathways for electrons to travel are shorter, allowing them to travel faster, and thus compute faster. However, the problem is that the more transistors you put on a semiconductor chip, the more heat it generates. This can eventually cause the chip to reach its performance limit. When heat is generated, the resistance of the transistors increases, the speed of the current drops dramatically, and the electrical signals are delayed, causing the circuit to become inaccurate and malfunction. This is why it is important to capture the heat generated by semiconductor chips.
Recently, there has been a major shift in the philosophy of scientists designing semiconductor chips. There’s been a shift in thinking, with the primary goal of designing to reduce heat, followed by how to increase speed. A prime example of this is the fact that the structure of transistors is changing to reduce the heat generated by semiconductor chips. These changes are having a major impact not only on the semiconductor industry, but on electronics in general. This is because future technological advances will be limited if we don’t solve the heat problem. A variety of innovative techniques are being tried to solve this problem, one of which is the use of new materials. Instead of traditional silicon-based transistors, new materials such as graphene and carbon nanotubes are being explored. These new materials have been touted as the next generation of semiconductor technology due to their ability to move electrons faster and generate less heat.
Let’s take a closer look at how heat is generated in transistors. The amount of current flowing between the source and drain of a transistor is regulated by the voltage across the gate and source. The gate acts as a floodgate to catch electrons traveling from the source to the drain. The electrons that escape the gate are the ones that generate heat in the transistor. However, as the distance between the source and drain electrodes became shorter, more electrons were able to escape from the source to the drain before the gate could catch them, resulting in more current leakage.
Various approaches have been proposed to solve this problem. To solve this problem, Dr. Hisamoto of Japan developed a “double-gate” transistor, which places two gates above and below the silicon passage through which current flows from the source to the drain. This doubles the floodgates that catch leakage current. This technology could significantly reduce heat generation, but its high manufacturing costs made it difficult to commercialize. Furthermore, Professor Collins in the United States developed the “front-gate” transistor, a structure in which the gate electrode covers the entire surface of the current passage. The floodgates guard the entire passage, preventing leakage current, which has been recognized as the most effective way to prevent heat from the transistor. These innovations don’t just reduce heat, they also maximize energy efficiency and have a positive environmental impact. This is a crucial factor for sustainable technology development.
