How to classify semiconductors

There are six classifications for semiconductors, which are classified by product standard, processing signal type, manufacturing process, usage function, application field, and design method.

1、 Classification by product standard

Semiconductors can be divided into four categories: integrated circuits, discrete devices, photoelectric devices, and sensors. Among them, integrated circuits are the most important.

Integrated circuits, namely, ICs, chips, and chips. Integrated circuits can be further divided into four sub areas: analog circuits, logic circuits, microprocessors, and memory. In mass media, sensors, discrete devices, etc. are also referred to as ICs or chips.

In 2019, integrated circuits accounted for 84% of global semiconductor product sales, far higher than 3% of discrete devices, 8% of photoelectric devices, and 3% of sensors.

2、 Classification by processing signal

A chip that processes more analog signals is an analog chip, and a chip that processes more digital signals is a digital chip.

Analog signals are simply signals that are continuously emitted, such as sound. The most common type in nature is analog signals. The corresponding is a discrete digital signal composed of 0 and 1 and non logic gates.

Analog signals and digital signals can be converted to each other. For example, the picture on a mobile phone is an analog signal, which can be converted into a digital signal through an ADC converter, processed by a digital chip, and finally converted into an analog signal through a DAC converter.

Common analog chips include operational amplifiers, digital to analog converters, phase locked loops, power management chips, comparators, and so on.

Common digital chips include general-purpose digital ICs and dedicated digital ICs (ASICs). General digital ICs include memory DRAM, microcontroller MCU, microprocessor MPU, and so on. A dedicated IC is a circuit designed for a specific user's specific purpose.

3、 Classification by manufacturing process

We often hear the term "7nm" or "14nm" chip, in which nanometers refer to the gate length of the transistor inside the chip, which is the minimum line width inside the chip. In short, it refers to the distance between lines.

The current manufacturing process takes 28 nm as the watershed, and those below 28 nm are referred to as advanced manufacturing processes. Currently, the most advanced manufacturing process in mainland China is SMIC's 14nm. TSMC and Samsung are currently the only companies in the world that plan to mass produce 5nm, 3nm, and 2nm.

Generally speaking, the more advanced the manufacturing process, the higher the performance of the chip, and the higher the manufacturing cost. Generally, the R&D investment for a 28nm chip design is as high as 1-2 billion yuan, while a 14nm chip requires 2-3 billion yuan.

4、 Classification by use function

We can analogize according to human organs:

Brain - Computational function, used for computational analysis, divided into main control chip and auxiliary chip. The main control chip includes a CPU, FPGA, and MCU, while the auxiliary chip includes a GPU in charge of graphics and image processing and an AI chip in charge of artificial intelligence computing.

Cerebral cortex - Data storage functions, such as DRAM, NAND, FLASH (SDRAM, ROM), etc.

Five senses - sensing functions, mainly including sensors, such as MEMS, fingerprint chips (microphone MEMS, CIS), etc.

Limbs - Transfer functions, such as Bluetooth, WIFI, NB-IOT, USB (HDMI interface, drive control) interfaces, for data transmission.

Heart - Energy supply, such as DC-AC, LDO, etc.

5、 Classification by application field

It can be divided into four categories, namely, civil grade, industrial grade, automotive grade, and military grade.

6、 Classification by design method

Today, there are two major camps for semiconductor design, one is soft and the other is hard, namely FPGA and ASIC. FPGA was developed first and is still the mainstream. FPGA is a general-purpose programmable logic chip that can be DIY programmed to implement various digital circuits. ASIC is a dedicated digital chip. After designing a digital circuit, the chip generated cannot be changed. FPGA can reconstruct and define chip functions with strong flexibility, while ASIC has stronger specificity.