Applications of Silicon Wafer in Semiconductors, Energy & Sensors

As explained in What is a silicon wafer, the wafer is the foundation for fabricating semiconductor devices. Below are the areas where silicon wafers play a core role.

1. Processors and memory

This is the largest application of silicon wafers. On each 300mm wafer, a fab can build hundreds of chips containing billions of transistors — including CPUs, GPUs, AI chips, DRAM and Flash memory. All computers, phones, servers and data centers rely on these chips.

2. Sensors and MEMS

Silicon wafers are the base for CMOS image sensors, accelerometers, gyroscopes, pressure sensors and microelectromechanical systems (MEMS) in phones, cars and medical devices.

3. Power electronics

In EVs, charging stations and energy systems, power modules based on Si and especially SiC (silicon carbide) wafers convert and control energy efficiently while tolerating high voltage and temperature.

4. Solar cells and renewable energy

Mono/poly crystalline silicon slices are the core of photovoltaic (solar) cells. Silicon wafers convert sunlight into electricity — a pillar of the rapidly growing renewable energy sector in Vietnam.

5. Photonics, LEDs and lasers

Wafers such as GaAs, Sapphire, InP serve as substrates for LEDs, laser diodes and photonic components used in lighting, displays and high-speed optical communications. See more in Types of Silicon Wafer.

6. Why is silicon wafer hard to replace?

• Abundant raw material: silicon is readily available in sand, keeping material cost low.
• Mature technology: decades of development built a huge manufacturing ecosystem.
• Ideal semiconductor properties: silicon easily forms a high-quality insulating oxide (SiO₂), ideal for transistor fabrication.
• Scalability: allows ever more transistors to be integrated in the same area.

7. From wafer to chip: what happens in between

A blank wafer does not become a chip by itself. It passes through hundreds of repetitions of four basic operations, each cycle building one more structural layer:

1. Deposition — lay down a new layer of material: oxide, nitride, polysilicon or metal, via CVD, sputtering or evaporation.
2. Lithography — print that layer's pattern into photoresist, defining what stays and what goes. Details in the photolithography process.
3. Etching — remove material where the resist does not protect it, transferring the pattern from resist into the real layer.
4. Ion implantation and annealing — fire dopant atoms into the silicon to form N- or P-type regions, then anneal to activate them and repair lattice damage.

Once front-end fabrication is complete, each die on the wafer is electrically probed, the wafer is diced, and the good dies are packaged and given a final test. It is precisely this packaging and test stage where Vietnam has held a position in the global semiconductor supply chain for years.

8. Why wafer diameters keep growing

The cost of processing one wafer barely depends on its diameter — one lithography step, one etch, one anneal cost about the same whether the wafer is large or small. But area, and therefore the number of dies, grows with the square of the radius.

Moving from 200 mm to 300 mm increases area by about 2.25× while per-step cost stays roughly flat. That economic pull drove the industry from 2 inch in the 1970s to 300 mm today. A further factor is often overlooked: larger wafers waste proportionally less area at the edge exclusion zone, because perimeter grows linearly while area grows quadratically.

Frequently asked questions