Fudan Develops New Microelectronic Devices

Recently, the research team led by Professor Zhang Wei, the deputy dean of the School of Microelectronics of Fudan University and the expert of the National 02 major special group, developed a new type of microelectronic device, the Semi-Floating Gate Transistor (SFGT), which allows data to be erased more easily. Easy, faster, and lower operating voltages provide the foundation for designing low-power chips. The relevant research results were published in the "Science" magazine published on August 8.

According to reports, Professor Zhang Wei’s team has long been engaged in the research of integrated circuit processes and semiconductor devices. This achievement has been called by industry scholars and may change the concerns of the IT industry in recent years: The development of technology will make it impossible for Moore's Law to reach its limit. This is also considered to be a new opportunity for China's microelectronics industry and may change the current domestic chip industry.

According to team member Professor Wang Pengfei, metal-oxide-semiconductor field-effect transistors (MOSFETs) are currently mainstream devices in integrated circuits. According to Moore's law, the feature size of transistors on chips is continuously shrinking, making the number of transistors on a chip It will double every 18 months. Advances in process over the past decades have allowed MOSFET transistors to shrink in size and become closer to their physical limits. The increase in the degree of integration makes the chip power density too large to face heat dissipation difficulties. Therefore, the industry has been trying to make breakthroughs in materials and circuit design, and actively looking for transistors based on new structures and new principles to break through the existing technological bottlenecks.

The forward-looking study of semi-floating-gate transistors started in this situation. The Fudan University team skillfully combined the tunneling transistor (TFET) with the floating-gate transistor to form a new “half-floating-gate” structure device called the semi-floating-gate transistor (SFGT). The “data” erasure of this transistor is easier and faster, and the whole process can be completed under low voltage conditions, which creates the conditions for low-power operation of the chip.

Semi-floating gate transistors have good application prospects in the areas of CPU cache, DRAM and CMOS image sensors, and have obvious advantages. For example, the CPU cache, now usually uses 6 MOS transistors to form a storage unit (SRAM), low integration, large area. About half of the area of ​​the 28nm Intel Xeon CPU is forced to be cached, greatly wasting resources. If the half-floating-gate transistor design cache circuit invented by Fudan University is used, a single transistor can constitute a memory cell, and the speed is equivalent to that of the traditional six MOS transistors, but the area occupied by the buffer can be reduced to a factor of ten. One, and reduce power consumption.