Low threshold voltage (Vt) is achieved by applying a thin dielectric cap between the gate dielectric and metal gate. In addition, the use of laser-only annealing for gate stack engineering resulted in a significant reduction of the minimum sustainable gate length and improved short-channel effect control. The same processes were applied on FinFETs and resulted in a possible candidate technology for the 22nm node.
A major challenge in using high-k dielectrics for CMOS devices is the high threshold voltage resulting in low performance. Dual metal gates in combination with dual dielectrics can solve this problem but have the drawback that extra processing steps are required resulting in a higher processing cost. IMEC developed a simpler, lower-cost integration scheme using only one dielectric stack and one metal. A thin dielectric cap is deposited between the gate dielectric and metal gate which effectively modulates the work function towards the optimal operating zone. Laser anneal instead of spike anneal is applied to reduce the effective oxide thickness. Using laser-only annealing higher activated and shallow junctions could be achieved.
Both a lanthanium- (La2O3) and dysprosium-based (Dy2O3) capping layer was used for nMOS and an aluminum-based capping layer for pMOS. Symmetric low Vt of +/-0.25V were achieved and drive currents of 1035µA/µm and 505µA/µm for nMOS and pMOS respectively at VDD of 1.1V and Ioff of 100nA/µm. Successful CMOS integration was illustrated by a ring oscillator delay of less than 15ps.
Since thin gate dielectrics suffer from soft breakdown before the specified lifetime and the failure is difficult to forecast, IMEC developed a time-dependent dielectric breakdown model to completely predict the reliability of the devices. The model is based on the statistical analysis of hard breakdown including multiple soft breakdown and wear out. By applying the model on the high-k/metal gate devices, the excellent quality of the gate dielectrics has been demonstrated.
In strong collaboration with NXP and TSMC, excellent performance (drive current of 950µA/µm and Ioff of 50nA/µm at VDD of 1V for nMOS FinFETs) and short channel effect control were achieved for tall, narrow FinFETs without mobility enhancement. Physical vapor deposition (PVD) and atomic layer deposition (ALD) were compared as metal deposition technique. Since PVD metals are denser and less porous, PVD of titanium nitride (TiN) electrodes on hafnium oxide (HfO2) dielectrics gave improved nMOS performance compared to ALD TiN. IMEC also applied the dysprosium-based (Dy2O3) capping process on FinFETs resulting in a possible candidate technology for the 22nm node.
These results were obtained in collaboration with IMEC’s (sub-)32nm CMOS core partners including Infineon, Qimonda, Intel, Micron, NXP, Panasonic, Samsung, STMicroelectronics, Texas Instruments and TSMC, and IMEC’s key CMOS partners including Elpida and Hynix.
Katrien Marent | alfa
Hope to discover sure signs of life on Mars? New research says look for the element vanadium
22.09.2017 | University of Kansas
22.09.2017 | Forschungszentrum MATHEON ECMath
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
22.09.2017 | Life Sciences
22.09.2017 | Medical Engineering
22.09.2017 | Physics and Astronomy