【Knowledge Discover】From Silicon to Gallium Oxide: Understanding Semiconductors, Wafers, Integrated Circuits, and Chips in One Article

      Semiconductors, chips, integrated circuits, and wafers are concepts that are closely interconnected and mutually dependent.

      Let us first look at semiconductors. What is a semiconductor? If we temporarily set aside terms such as the “semiconductor industry” or “semiconductor sector” and focus purely on the material itself, a semiconductor is a class of materials whose electrical conductivity lies between that of conductors (such as copper) and insulators (such as glass). The conductivity of semiconductors can be controlled through doping (the introduction of small amounts of impurities) or external conditions such as temperature and light. One of the key characteristics of semiconductors is their controllable conductivity—for example, doping can create N-type or P-type semiconductors. They also exhibit special properties such as thermal sensitivity and photosensitivity.

      Common semiconductor materials include silicon (Si, the most widely used), germanium (Ge), and gallium arsenide (GaAs). In recent years, with the rapid development of power electronics and advanced optoelectronic devices, new wide-bandgap semiconductor materials such as Gallium Oxide (Ga₂O₃) have attracted increasing attention. Compared with traditional silicon, Gallium Oxide features a wider bandgap and a much higher theoretical breakdown electric field, making it promising for applications in high-voltage power devices and deep-ultraviolet optoelectronic devices.

      Semiconductors serve as the fundamental materials of modern electronic technology and are widely used to fabricate electronic components such as transistors, diodes, and integrated circuits.

      So what is a wafer? A wafer is a circular thin slice made from high-purity single-crystal semiconductor material through processes such as slicing and polishing. It serves as the key substrate for manufacturing integrated circuits and various semiconductor devices.

      In the traditional integrated circuit industry, wafers are typically made from high-purity single-crystal silicon. The manufacturing process generally involves extracting high-purity silicon from quartz sand, growing single-crystal silicon ingots through crystal-pulling processes, slicing the ingots into thin wafers, and then performing precision grinding and polishing to produce finished wafers (commonly with diameters of 8 or 12 inches).

      In addition to silicon wafers, new materials are increasingly used in next-generation power semiconductor technologies, including silicon carbide (SiC), gallium nitride (GaN), and Gallium Oxide (Ga₂O₃). Among them, Gallium Oxide single crystals can be grown using melt-growth methods and processed into wafers, providing the material foundation for high-voltage power devices and ultraviolet optoelectronic devices.

      Wafers are often described as the “canvas” of integrated circuit manufacturing because various electronic components—such as transistors, resistors, and capacitors—are built layer by layer on the wafer surface through processes such as photolithography and etching. In essence, a wafer is a critical carrier made from semiconductor materials and prepared through a series of precision manufacturing processes.

      What, then, is an integrated circuit?

      An integrated circuit (IC) is a microelectronic circuit in which a large number of electronic components—such as transistors, resistors, and capacitors—are integrated onto a single semiconductor chip. Through circuit design, these components work together to perform specific functions such as computation, data storage, and signal processing. Integrated circuits are characterized by miniaturization, high performance, and low power consumption.

      According to their functions, integrated circuits can generally be classified into digital ICs (such as CPUs and GPUs), analog ICs (such as amplifiers), and mixed-signal ICs. From a manufacturing perspective, integrated circuits are built on wafers through a sequence of processes including photolithography, etching, and doping. After the circuit structures are completed, the wafer is then diced into individual IC dies.

      It is worth noting that most integrated circuits today are still based on silicon. In contrast, emerging semiconductor materials such as Gallium Oxide are currently used mainly in power devices—such as Schottky barrier diodes and MOSFETs—as well as deep-ultraviolet photodetectors. These materials are considered important directions for the development of third-generation and ultra-wide-bandgap semiconductors.

      Finally, what is a chip?

      A chip is the physical form of an integrated circuit and usually refers to the packaged integrated circuit product. At its core is the integrated circuit itself, while the packaging process provides pins or pads that allow the device to connect with external circuits (for example, the black square packages seen on CPUs or memory modules). Chips can be directly used in various electronic devices to perform functions such as computation, storage, and control—for instance, smartphone processors or graphics chips.

      In the field of power electronics, power chips based on materials such as silicon carbide, gallium nitride, and Gallium Oxide are also gradually emerging. These devices are mainly used in applications requiring high efficiency and high voltage tolerance, such as electric vehicles, power systems, and industrial equipment.

      In simple terms, semiconductors are the fundamental materials, wafers serve as the manufacturing platform, integrated circuits represent the technological outcome of design and fabrication, and chips are the final products. Their basic relationship can be summarized as:

      Semiconductor materials (such as Si and Ga₂O₃) → Wafer → Integrated Circuit (IC) → Chip

      Taking the smartphone processor as an example: silicon material is first fabricated into wafers. Billions of transistors are then integrated on the wafer through a series of fabrication processes to form an integrated circuit. After packaging, the device becomes a chip, which is finally mounted on the smartphone motherboard to perform computing and control functions.

      In emerging power electronics applications, chips based on Gallium Oxide wafers may also appear in the future, enabling higher voltage tolerance and lower power losses in energy conversion and control systems.