Low noise clock generator; on-chip thermal sensor; carbon nanotube sandpaper.
Researchers from Ulsan National Institute of Science and Technology (UNIST) designed a low power semiconductor circuit capable of generating high-quality clock signals with significantly reduced noise levels.
The injection-locked clock multiplier (ILCM) circuit uses a simplified design based on a ring voltage-controlled oscillator (VCO). It integrates a frequency tracking loop and a timing calibration method that dynamically optimize the injection timing to suppress reference spur noise without increasing circuit complexity or power consumption.
“Injection locking offers a fast and efficient way to generate high-frequency clock signals, but the residual reference spur has always limited system performance,” said Heein Yoon, a professor in the department of electrical engineering at UNIST, in a statement. “Our design reduces this noise with a simple, yet highly effective, circuit structure—opening new avenues for high-speed, low-power semiconductor systems.”
Fabricated using 28nm CMOS technology, the circuit occupies 0.0444 mm² and consumes only 12.28 mW of power. At a frequency of 2.1 GHz, the researchers said it achieved a record-low reference spur level of -81.36 dBc, along with an ultra-low jitter of only 280.9 fs, making it suitable for ultra-high-speed applications. [1]
Researchers from Penn State, University of Chemistry and Technology Prague, and Northwestern University developed a thermometer using 2D materials that can be integrated onto a chip to accurately track temperatures.
The sensors are based on bimetallic thiophosphates, a class of 2D material in which ions can continue to effectively move even when exposed to electrical currents. The 2D material couples together the transport of both ions and electrons and allows the sensor to operate using the chip’s electrical current to provide extremely sensitive temperature readings in 100 nanoseconds, without a notable impact on chip performance.
“We found that using this class of material, we could develop thermal sensors that are very fast, low power and really miniaturized so that you can place many of them on a single chip,” said Saptarshi Das, professor of engineering science at Penn State, in a press release. “What is generally unwanted by industry in transistors actually is great for thermal sensing, so we really tried to exploit that in our design. Rather than try to remove these ions from this system, we use them to our advantage. Coupling these ions for temperature sensing and electrons for reading that thermal data allows us to have an extremely accurate but compact device.”
The researchers said the sensor is more than 100 times smaller than other leading sensor designs, enabling them to place thousands of the sensors on a single chip. Since it doesn’t need extra circuitry or signal converters, it is also up to 80 times more power efficient than traditional silicon-based systems. [2]
Researchers from the Korea Advanced Institute of Science and Technology (KAIST) developed a carbon nanotube ‘sandpaper’ for uniform atomic level processing of semiconductor surfaces without the nuisance and waste of slurry solutions.
The sandpaper is constructed by vertically aligning carbon nanotubes, fixing them inside polyurethane, and partially exposing them on the surface. The structure suppresses abrasive detachment and maintained stable performance even after repeated use.
At 258 billion grit, it can process surfaces with precision down to several nanometers, which the team demonstrated by polishing rough copper surfaces. Additionally, in semiconductor pattern planarization experiments, the technique reduced dishing defects by up to 67% compared with conventional chemical mechanical polishing (CMP) processes. It also reduces necessary cleaning steps.
Professor Sanha Kim stated, “This is an original study demonstrating that the everyday concept of sandpaper can be extended to the nanoscale and applied to ultra-fine semiconductor manufacturing,” said Sanha Kim, a professor in the department of mechanical engineering at KAIST, in a release. “We hope this technology will lead not only to improved semiconductor performance but also to environmentally friendly manufacturing processes.” [3]
[1] H. Nam, H. An, C. An, S. Kim and H. Yoon, “A Low-Reference-Spur Injection-Locked Clock Multiplier Using Sub-Sampling Frequency Tracking Loop and Injection Pulse Timing Calibrator,” in IEEE Journal of Solid-State Circuits. https://dx.doi.org/10.1109/jssc.2025.3650135
[2] D. Sen, A. Chowdhury, S. Imam, et al. Solid-state thermometry via ionic–electronic coupling in two-dimensional heterostructures. Nat. Sens. (2026). https://doi.org/10.1038/s44460-026-00034-2
[3] S. Kang, Jh. Jeong, H.J. Ryu, G. Park, S. Kim. Carbon nanotube sandpaper for atomic-precision surface finishing. Adv Compos Hybrid Mater 9, 44 (2026). https://doi.org/10.1007/s42114-025-01608-3
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