Chinese team achieves major breakthrough in carbon nanotube CFET architecture
Researchers at Peking University have developed the first all-carbon nanotube CFET digital logic circuits, achieving highly balanced electrical performance between p-type and n-type transistors. This advancement is significant for the future of carbon nanotube technology, as it introduces a new path for high-density computing architectures in artificial intelligence and edge computing applications.
A research team from Peking University's School of Electronics, led by Xuelei Liang, has developed the first all-carbon nanotube complementary field-effect transistor (CFET) digital logic circuits. This advancement addresses the challenges of mismatched drive capability between p-type and n-type carbon nanotube transistors and performance degradation from upper-layer fabrication. The team employed a dopant-free CMOS approach and optimized the device architecture, achieving balanced electrical performance between the top-layer n-FET and bottom-layer p-FET.
The fabricated CFET inverter demonstrated excellent rail-to-rail voltage transfer characteristics and low-power operation across a supply voltage range of 0.2–1.0 V. At 1.0 V, it achieved a peak voltage gain of 164, the highest reported for low-dimensional semiconductor CFET inverters. The device also exhibited high stability and a large noise margin of 61%–80% Vdd. The team successfully demonstrated NOR, OR, NAND, and AND gates, a four-transistor static random-access memory (4T-SRAM) cell, and the first five-stage ring oscillator based on an all-carbon nanotube CFET architecture.
Leveraging the dual-layer carbon nanotube structure, the researchers developed a three-dimensional stacked photodiode that enhances light utilization and delivers an open-circuit photovoltage nearly twice that of a single-layer device. By coupling the photodiode output directly to the CFET inverter input, they demonstrated the first monolithically integrated three-dimensional carbon nanotube sensing-computing circuit. This prototype performs optical power and spectral sensing alongside logic processing across a wavelength range of 1,200–1,900 nm, achieving a minimum switching power of just 45 μW at 1,900 nm.
This development fills a critical gap in carbon nanotube CFET research and introduces a new pathway for high-density near-sensor and in-sensor computing architectures, with potential applications in artificial intelligence and edge computing.
Source: Carbon Nanotubes Feed