In a significant advancement for microelectronics, a research team led by Prof. Jianhua Hao at The Hong Kong Polytechnic University (PolyU) has developed a novel tunnelling field-effect transistor (TFET) that overcomes the physical limits of conventional semiconductor technology. The breakthrough, published in the journal Science, could pave the way for energy-efficient computing and next-generation AI chips.
Conventional transistors rely on thermionic emission, which requires a minimum gate voltage of 60 millivolts (mV). This 'Boltzmann limit' restricts subthreshold swing values to 60 mV per decade at room temperature, hindering progress in high-performance electronics. Prof. Hao's team adopted quantum tunnelling to bypass this barrier, achieving subthreshold swing values well below the theoretical limit.
By creating ultra-thin heterostructures of 2D bismuth and indium selenide using pulsed laser deposition, the researchers transformed semi-metallic bismuth into a semiconductor in 2D form. This allowed charge carriers to tunnel efficiently into indium selenide, resulting in a device that operates at room temperature on silicon substrates with a gate-voltage range of only 160 mV—far lower than the 800 mV typically required.
The TFET also delivers a high output current and an exceptionally high ON/OFF current ratio, addressing challenges in experimental TFETs and enabling multiple downstream logic gates while reducing circuit delay. The collaboration involved the National University of Singapore, The Hong Kong University of Science and Technology, Peking University, and the Singapore University of Technology and Design.
This development is crucial as the semiconductor industry faces physical limits in transistor miniaturization and energy efficiency. By breaking the Boltzmann limit, the TFET offers a path to ultra-low-power, high-performance integrated circuits essential for emerging AI chips and advanced semiconductor applications. The research provides fundamental insights that could lead to more efficient and powerful electronic devices, impacting everything from consumer electronics to data centers.
The study's implications extend beyond computing: more efficient transistors could reduce energy consumption in electronic devices, contributing to sustainability goals. It also opens new possibilities for integrating 2D materials into existing semiconductor manufacturing processes, potentially accelerating the commercialization of next-generation chips.
The team's work demonstrates the potential of quantum tunnelling in practical devices, marking a step forward in semiconductor technology. As AI applications demand ever-increasing computational power, such breakthroughs are vital to meet performance needs while managing energy constraints.
