Who will be the leader in the fifth-generation semiconductors?
From the first - generation silicon - based semiconductors that supported the computer revolution to the subsequent generations of materials that opened the era of optoelectronics and new energy, each generational change has triggered a wave of leap - forward transformation in key fields such as communications, energy, and computing.
An in - depth analysis of the characteristics, application scenarios, and the logic behind the generational changes of the first four generations of semiconductor materials not only allows us to clearly understand the historical context of semiconductor development but also provides key evidence for speculating on the possible direction of the fifth - generation semiconductors.
01 From the First Generation to the Fourth Generation: The Iterative Path of Semiconductor Materials
The first - generation semiconductor materials are the earliest semiconductors used on a large scale by humans, mainly two elemental semiconductors: silicon (Si) and germanium (Ge). Among them, silicon materials have established a core position in modern electronic industries such as integrated circuits, computers, and communication devices, thanks to their 1.12eV bandgap, abundant crustal reserves (about 26.4%), and mature manufacturing processes.
The second - generation semiconductor materials are compound semiconductor materials that emerged in the 1980s and 1990s with the development of mobile communications and optical fiber communications, mainly represented by gallium arsenide (GaAs) and indium phosphide (InP). Due to their high - frequency, high - speed, and high - power characteristics, these materials are suitable for manufacturing microwave devices, millimeter - wave devices, and light - emitting electronic devices, gradually breaking through the performance limitations of traditional silicon - based materials. Their bandgap lies between those of the first - and third - generation semiconductors and is mainly used in fields such as satellite communications, mobile communications, and optical communications. Semiconductor lasers in optical communication systems and 5G millimeter - wave systems both rely on this material.
Since the 21st century, the third - generation semiconductor materials represented by gallium nitride (GaN) and silicon carbide (SiC) have begun to stand out. The third - generation semiconductor materials have characteristics such as a wider bandgap, higher thermal conductivity, higher radiation resistance, and a larger electron saturation drift rate, making them more suitable for manufacturing high - temperature, high - frequency, radiation - resistant, and high - power electronic devices, and having important application values in the fields of optoelectronics and microelectronics. The popular 5G base stations, new energy vehicles, and fast - charging technologies in the market are all important application fields of the third - generation semiconductors.
The fourth - generation semiconductors are ultra - bandgap semiconductors, mainly in two directions. One is ultra - wide bandgap semiconductors represented by gallium oxide, and the other is narrow - bandgap semiconductors such as antimonide semiconductors.
So, what will the fifth - generation semiconductors be?
02 Topological Insulators: The Hope for Zero - Energy - Consumption Electronic Devices
Topological insulators are a new type of quantum material with a special electronic structure. Their most prominent characteristic is that the surface or boundary has a conductive state, while the interior shows an insulating state. This unique "bulk - insulating - surface - conductive" quantum characteristic makes them regarded as the core material for the next - generation ultra - low - power chips.
From a physical mechanism perspective, the surface conductive state of topological insulators is determined by the topological properties of the material and has topological protection characteristics, that is, it is not easily affected by factors such as surface defects and impurities in the material. Electrons experience almost no scattering during surface transmission and can achieve dissipation - free transmission, which means that electronic devices made of topological insulators can significantly reduce energy consumption and solve the heating problem of traditional semiconductor devices caused by electron scattering. In addition, the surface electrons of topological insulators also have a spin - momentum locking characteristic, that is, there is a fixed corresponding relationship between the electron's spin direction and momentum direction. This characteristic provides new ideas for the research and development of spintronic devices and is expected to achieve higher - density and faster - speed information storage and processing.
Since the concept of topological insulators was proposed, researchers have made a series of important breakthroughs in material preparation, performance characterization, and device research and development. In terms of material preparation, various types of topological insulator materials have been successfully prepared, including three - dimensional topological insulator materials such as bismuth telluride (Bi₂Te₃), bismuth selenide (Bi₂Se₃), and bismuth antimonide (BiSb), as well as some two - dimensional topological insulator materials. Through the optimization of preparation processes such as molecular beam epitaxy and chemical vapor deposition, the crystal quality and surface flatness of the materials have been continuously improved, laying a good foundation for subsequent device research and development. In terms of performance characterization, using advanced characterization techniques such as angle - resolved photoemission spectroscopy (ARPES), researchers have clearly observed the Dirac cone electronic structure on the surface of topological insulators, confirming the existence of the surface conductive state, and have also conducted in - depth research on electron transport characteristics, spin characteristics and so on. In terms of device research and development, prototype devices such as field - effect transistors, spin filters, and qubits based on topological insulators have been initially developed. For example, field - effect transistors based on topological insulators exhibit extremely low leakage currents and good switching characteristics, showing potential applications in low - power logic circuits. Topological insulator spin filters can effectively control electron spin, taking an important step towards the practical application of spintronic devices. However, the research and development of topological insulators still face some challenges, such as how to further improve the carrier mobility of materials, reduce defect density, and how to achieve large - scale device preparation. These problems need to be continuously solved by researchers in future studies.
03 Two - Dimensional Materials: The Key to Breaking the Bottleneck of Moore's Law
Two - dimensional materials refer to sheet - like materials with a nanoscale or atomic - scale thickness in one dimension and a macroscopic scale in the other two dimensions. Typical representatives include graphene and molybdenum disulfide (MoS₂). The atomic - level thickness endows two - dimensional materials with unique electrical, optical, and mechanical properties.
Facing the global challenge of Moore's Law approaching its physical limit, two - dimensional semiconductors with a single - atomic - layer thickness are currently recognized internationally as the key to breaking the bottleneck, and scientists have been exploring how to apply two - dimensional semiconductor materials to integrated circuits. In fact, two - dimensional materials have been added to the IMEC logic scaling roadmap.
For more than a decade, the international academic and industrial communities have mastered the wafer - scale growth technology of two - dimensional materials and successfully manufactured high - performance basic devices with a length of hundreds of atoms and a thickness of several atoms. However, the highest integration level of two - dimensional semiconductor digital circuits internationally was only 115 transistors, achieved by a team from the Vienna University of Technology in Austria in 2017. The core problem is that assembling these atomic - level precision components into a complete integrated circuit system is still restricted by the coordinated yield control of process accuracy and scale uniformity.
Earlier this year, the joint team of Zhou Peng and Bao Wenzhong from the State Key Laboratory of Integrated Chip and System at Fudan University successfully developed the world's first 32 - bit RISC - V architecture microprocessor "WUJI" based on two - dimensional semiconductor materials. This achievement breaks through the engineering bottleneck of two - dimensional semiconductor electronics and for the first time achieves an integration level of 5900 transistors. It is a domestic technology completed by the Fudan team with independent intellectual property rights, enabling China to take the lead in the research and development of new - generation chip materials and providing strong support for promoting electronics and computing technology into a new era.
04 Carbon Nanotubes: New Channel Materials
In semiconductor devices, the channel is the key area for electron or hole transport. The performance of the channel material directly determines key indicators such as the device's switching speed, driving current, and power consumption. As semiconductor manufacturing processes continue to approach the physical limit, the performance improvement space of traditional silicon - based channel materials is gradually limited. Therefore, the research and development of new channel materials has become a key breakthrough point for improving the performance of semiconductor devices and is also an important research direction for the fifth - generation semiconductors. Among them, carbon nanotubes (CNTs) are the most representative new channel materials.
As early as 2007, carbon - based nanoelectronics was proposed as a potential next - generation electronic technology. The main reasons are as follows: (1) Carbon and silicon belong to the same main group of elements and have many similar chemical properties; (2) The length of CNTs is several hundred nanometers, and the electron transport in the device shows a perfect ballistic structure, with high energy utilization efficiency; (3) The ultra - thin conductive channel has high carrier mobility, minimizing the short - channel effect of ultra - scale FETs at technology nodes less than 10nm; (4) Excellent thermal conductivity. However, the premise for preparing carbon nanotube integrated circuits is to achieve conditions such as ultra - high semiconductor purity, appropriate density, and consistent arrangement direction of CNTs. Manufacturing carbon nanotube materials that meet the requirements is a huge challenge for carbon nanotube electronics.
Carbon nanotube transistors are transistors made with carbon nanotubes as the core channel conductive material, and their performance has broken through the limitations of traditional silicon - based transistors. In 2016, a team from the University of Wisconsin in the United States developed a 1 - inch carbon nanotube transistor. By using polymer to replace metal nanotubes, the metal impurity content was reduced to less than 0.01%, solving the bottleneck of conductive performance. In the latest progress in 2025, a team from Peking University developed a 90nm integrated carbon nanotube hydrogen sensor, and MIT used more than 14,000 carbon nanotubes to make a 16 - bit microprocessor. Such transistors show application potential in fields such as radiation - resistant integrated circuits, but still face challenges such as the optimization of manufacturing processes.
05 Quantum Dots and Photonic Crystals
Quantum dots are nanoscale semiconductors. When a certain electric field or light pressure is applied to these nanoscale semiconductor materials, they will emit light of a specific frequency, and the frequency of the emitted light will change with the size of the semiconductor. Therefore, by adjusting the size of the nanoscale semiconductor, the color of the emitted light can be controlled. Since these nanoscale semiconductors have the characteristic of confining electrons and electron holes (Electron hole), which is similar to atoms or molecules in nature, they are called quantum dots.
Photonic crystals refer to artificial periodic dielectric structures with photonic band - gap (Photonic Band - Gap, abbreviated as PBG) characteristics, and are sometimes also called PBG photonic crystal structures. The so - called photonic band - gap means that waves in a certain frequency range cannot propagate in this periodic structure, that is, there is a "forbidden band" in this structure itself, which can be used to control the emission, transmission, and reflection of photons. Photonic crystals are very small in volume and have broad application prospects in new nanotechnologies, optical computers, chips and other fields.
The combination of quantum dots and photonic crystals can achieve multi - functional integration of light - electricity - heat and has broad application prospects in the field of optoelectronic devices.
06 Biological Semiconductors
Biological semiconductors are a new type of semiconductor material based on biomolecules (such as DNA and proteins). Their core feature is the ability to be compatible with biological systems and electronic circuits, enabling efficient conversion and interaction between biological signals and electronic signals. For example, proteins have unique molecular structures and electrical properties and can be used to prepare biological semiconductor devices, such as protein storage devices. These devices use the charge - storage properties of protein molecules to store information and have advantages such as high density, low power consumption, and good biocompatibility.
In terms of R & D progress, biological semiconductors are currently in the early stage of laboratory research, but some remarkable results have been achieved. Researchers have successfully achieved the ordered arrangement and functional modification of biomolecules such as DNA and proteins through technologies such as genetic engineering and molecular self - assembly, and prepared biological thin films and nanostructures with semiconductor properties. Prototype devices based on these biological materials, such as biological field - effect transistors, biosensors, and protein memories, have been developed one after another, initially verifying the application potential of biological semiconductors in fields such as biomedical detection, wearable electronic devices, and new - generation information storage. However, the development of biological semiconductors still faces many challenges. For example, biomolecules have poor stability and are easily affected by the external environment (such as temperature, humidity, and pH value). How to improve the stability and reliability of biological semiconductor materials and devices; it is difficult to regulate the electrical properties of biomolecules. How to achieve precise control of their electrical characteristics; and the preparation process of biological semiconductor devices is complex, making it difficult to achieve large - scale production. These are all problems that need to be focused on and solved in the future.
07 Summary
The development of the fifth - generation semiconductors is in the exploration and initial stage. Candidate materials such as topological insulators, two - dimensional materials, new channel materials, quantum dots and photonic crystals, and biological semiconductors each have their own characteristics and are expected to play important roles in future technological development.
Although these materials still face many technical challenges at present, with the continuous in - depth research and continuous technological breakthroughs, the fifth - generation semiconductors will surely bring new changes to human technology and promote leap - forward development in fields such as communications, energy, computing, and biomedicine.
This article is from the WeChat public account "Semiconductor Industry Perspective" (ID: ICViews), author: Peng Cheng, published by 36Kr with authorization.