Report
Teaser, summary, work performed and final results
Periodic Reporting for period 2 - Milli-Tech (Milli-Volt Switch Technologies for Energy Efficient Computation and Sensing)
Teaser
The Milli-Tech proposal aims at a novel technology platform serving both computation and sensing: electronic switch architectures, called steep slope switches, exploiting new device physics and concepts in emerging 2D materials to achieve operation at voltages below 100...
Summary
The Milli-Tech proposal aims at a novel technology platform serving both computation and sensing: electronic switch architectures, called steep slope switches, exploiting new device physics and concepts in emerging 2D materials to achieve operation at voltages below 100 millivolts. Such switches will have a subthreshold slope below 10mV/decade, significantly more abrupt than MOSFET thermal limit of 60mV/decade at room temperature and in great advance to any beyond CMOS switches. Such characteristics will dramatically improve both the energy efficiency of logic circuits and the transduction sensitivity for many classes of sensors.
The project will develop a technological platform called ‘millivolt technology’ focusing on low power digital and sensing/ analog electronic functions exploiting steep slopes, with the goal of lowering the energy per useful function (computed and sensed bit of information) by a factor of 100x. Such ultra-low operation voltage will contribute to solving major challenges of nanoelectronics such as power issues and it will enable energy efficient super-sensitive sensors for Internet-of-Everything (IoE). Milli-Tech includes fundamental research on new solid-state steep slope device concepts: heterostructure tunnel FETs in 2D Transition-Metal-Dichalcogenides (TMD), 2D Van der Waals super-lattice energy filter switch and hybrid architectures combining two switching principles: band-to-band-tunneling and metal-insulator-transition or negative capacitance in VO2, used as additive technology boosters.
Milli-Tech plans breakthroughs by precise demonstrators:
(i) energy efficient computation blocks for Von-Neumann ICs at sub-100mV;
(ii) Active Pixel Sensors based on 2D TMD/GeSn tunnel FETs for IR imagers;
(iii) Terahertz detectors based on hybrid 2D VO2/TMD switches (iii) ultra-sensitive 2D steep slope charge detectors for biosensing.
The high-risk ‘millivolt technology’ will bring 2D materials on established advanced CMOS platforms and will be highly rewarding by enabling the energy efficient revolution needed for the Internet of Things.
Work performed
The first period of MilliTech reporting was dealing with the following implementation steps, which have been achieved:
• Hiring of the PhD students according to the workplan and the scientific objectives of the project.
• Ordering, installing, calibrating and accepting the Pulsed Laser Deposition (PLD) equipment needed for producing the hybrid devices using phase change VO2 material and 2D materials. This equipment is currently able to produce layers of VO2 with thicknesses of less than 50nm in which the MIT switching has been demonstrated.
• Realizing the very first technological proof of concepts in terms of fabricated devices and their characterization followed by the first publications supported in MilliTech.
• Participation of the MilliTech team in international events. The most remarkable was the participation of three Millitech members (2 PhDs and the PI) in IEEE International Electron Devices Meeting 2017, San Francisco, the leading international conference in micro/nanoelectronics. Nicolo Oliva presented the first hybrid VO2/MOS2 junction transistor, Francesco Bellando reported a demonstration of functionalizations of gate stacks on thin SOI FETs for electrolyte sensing (his work being included in the press kit of the conference), and prof. Adrian Ionescu presented a keynote talk centred on the core theme of MilliTech: Energy efficient computing and sensing in the Zettabyte era: from silicon to the cloud. During the reporting period, the project produced 11 conference and journal contributions (and another 2 have been accepted early 2018).
Final results
In terms of major achievements beyond the state of the art for the period of reporting, these are related to:
(i) the realization of first ever van der Waals devices based on VO2/MOS2 junctions and their use for electronic switching and for light detection;
(ii) the achievement of the first ever Hybrid Phase-Change – Tunnel FET (PC-TFET) Switch with Subthreshold Swing < 10mV/decade and sub-0.1 body factor that has been benchmarked for both digital and analog applications;
(iii) the realization of the functionalization of HfO2 gate stacks to selectively detect electrolytes in sweat that is currently transferred to 2D tunnel FET sensors;
(iii) the optimization of a technological process for the transfer of 2D material flakes with improved control that enabled the fabrication of various classes of 2D devices.
(iv) the realization of complementary 2D FETs (n- and p-type) based on 2D BP material, by engineering the workfunctions of the metal contacts.
Website & more info
More info: https://actu.epfl.ch/news/prof-mihai-adrian-ionescu-has-been-awarded-an-erc-/.