CoolCAD Electronics is a leading provider of electrical test services (current-voltage, capacitance-voltage, noise, transients, etc.) and compact modeling (SPICE) for companies and agencies fabricating and/or designing electronics for low temperature operation. CoolCAD Electronics is a leading-edge company specializing in cryogenic electronics design, testing, and characterization of semiconductor devices operating at ultralow temperatures. With the growing importance of cryogenic technologies in fields like quantum computing, superconducting circuits, and high-performance computing, CoolCAD addresses the unique challenges posed by extreme environments. The company’s work enables precise device characterization at temperatures as low as 4 K, offering insights into semiconductor behavior and performance in cryogenic conditions. As demand for robust, high-performance cryogenic electronics increases, CoolCAD provides the tools and expertise required to ensure reliability and functionality in these challenging environments.

Cryogenic testing presents challenges that conventional room-temperature testing methods cannot address. Near absolute zero, semiconductor materials undergo significant changes in electrical properties, including variations in carrier mobility, material structure, and electron trapping behaviors. These effects can lead to performance degradation that traditional testing systems cannot detect. CoolCAD has developed state-of-the-art testing platforms to capture these temperature-induced phenomena with unprecedented accuracy. Their advanced equipment, such as ultra-fast I-V (current-voltage) measurement systems, allows engineers and researchers to observe device behavior at cryogenic temperatures in real time, with a time resolution down to 20 nanoseconds. This ability to conduct fast timescale measurements is crucial for uncovering complex transient dynamics in cryogenic devices.

One of CoolCAD’s key innovations is its ultrafast I-V measurement system, which enables detailed analysis of charge trapping and de-trapping dynamics in low temperature semiconductor devices. Charge traps—often caused by defects or impurities—can impact cryogenic circuit performance, especially in applications where precision and reliability are paramount, such as quantum computing. By tracking shifts in device parameters like threshold voltage and transconductance (gm), CoolCAD’s testing platform provides insights into both fast and slow charge traps that degrade performance. These measurements are essential for understanding cryogenic device operation and play a critical role in high-performance cryogenic electronics development.

The ultrafast I-V measurement system developed by CoolCAD and NIST researchers also allows analysis of transient effects over a broad range of pulse durations, from nanoseconds to milliseconds. This flexibility enables researchers to capture both fast, short-lived phenomena and slower, thermally driven trapping events. The ability to observe both behaviors is essential for understanding device operation in low-temperature environments. For example, some charge traps may be linked to interface states that become apparent only at cryogenic temperatures. By capturing these effects, CoolCAD’s technology identifies potential performance bottlenecks, allowing engineers to optimize device performance before deployment in real-world applications.

In addition to its testing capabilities, CoolCAD is innovating in semiconductor device modeling and simulation for cryogenic environments. Temperature-induced effects can alter material and device behavior unpredictably, making accurate modeling essential for reliable low-temperature device design. CoolCAD’s simulation tools help engineers anticipate how different materials and design choices will respond in cryogenic conditions, supporting a holistic approach to cryogenic electronics and enabling the development of optimized, reliable devices.

CoolCAD Electronics also emphasizes the importance of understanding materials science and device physics for successful cryogenic electronics. The company’s experts work closely with researchers, engineers, and institutions to bridge fundamental materials research and applied device engineering. This collaborative approach drives the development of novel semiconductor materials, such as high-k dielectrics, essential for cryogenic circuit performance. CoolCAD’s solutions help create devices that operate efficiently in demanding cryogenic regimes by understanding material interactions with the environment. The company’s work is especially relevant to quantum computing, where precision and reliability are critical for the stable operation of qubits and other low temperature components. CoolCAD’s testing platforms help ensure these devices operate as intended at the cryogenic temperatures required for quantum operations. By providing a detailed understanding of device behavior at ultralow temperatures, CoolCAD advances the performance and scalability of quantum technologies, which rely on precise quantum state control.
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Figure 1: Top view of the cryogenic probe station showing all the probes and high-speed cables in the chamber with devices under test and the cold sample stage that is temperature controlled down to ∼4 K. Low temperature capacitance voltage measurements are used to characterize various CMOS technology nodes. Credit: CoolCAD

Figure 2: Gate voltage dependent drain current versus drain voltage curves of a narrow device (W/L = 10/0.27, both dimensions are in micrometers) measured at 4K. These measurements along with measurements of other size devices are used to extract a SPICE model card. The simulated curves (black lines with + symbol) are compared with an example set of measurements Credit: CoolCAD

Figure 3: The CMOS device measurements obtained in a low temperature probe station show that the drive current of a CMOS device usually increases with temperature decreasing. In addition to current voltage and capacitance-voltage measurements, we regularly perform 1/f and random telegraph noise experiments. A typical 1/f time domain signal and its frequency domain counterpart are shown on the right. Credit: CoolCAD

Figure 4: Two of our low and high temperature probing setups are shown here. Using these setups, we perform chip measurements from 4 K to 1000 K, with current and voltage ranges spanning from a fraction of a picoamp to an amp, and a microvolt to hundreds of volts, respectively. These also allow for the measurement of a fraction of a picofarad. Credit: CoolCAD