Potential of thin-film sensors in infrared imaging.

Thin-film pinned photodiode integrated into superior short-wave-infrared imaging sensors.

The successful integration of a pinned photodiode structure in thin-film image sensors has been presented by Imec^*. With the addition of a pinned-photogate and a transfer gate, the superior absorption qualities of thin-film imagers -beyond one µm wavelength- can finally be exploited, unlocking the potential of sensing light beyond the visible in a cost-efficient way. Detecting wavelengths beyond visible light, for instance infrared light, offers clear advantages. Applications include cameras in autonomous vehicles to ‘see’ through smoke or fog and cameras to unlock your smartphone via face recognition. Whilst visible light can be detected via silicon-based imagers, other semiconductors are necessary for longer wavelengths, such as short-wave infrared (SWIR).

Pawel Malinowski, imec Program Manager ‘Pixel Innovations’ adds: “At imec, we are at the forefront of bridging the worlds of infrared and imagers, thanks to our combined expertise in thin-film photodiodes, IGZO, image sensors and thin-film transistors. By achieving this milestone, we surpassed current pixel architectural limitations and demonstrated a way to combine the best performing quantum-dot SWIR pixel with affordable manufacturing. Future steps include optimization of this technology in diverse types of thin-film photodiodes, as well as broadening its application in sensors beyond silicon imaging. We are looking forward to further these innovations in collaborations with industry partners.”

Use of III-V materials can overcome this detection limitation. However, manufacturing these absorbers is expensive, limiting their use. In contrast, sensors using thin-film absorbers (such as quantum dots) have recently emerged as a promising alternative. They have superior absorption characteristics and potential for integration with conventional (CMOS) readout circuits. Nonetheless, such infrared sensors have an inferior noise performance, which leads to poorer image quality.

Already in the 1980’s, the pinned photodiode (PPD) structure was introduced for silicon-CMOS image sensors. This structure introduces an additional transistor gate and a special photodetector structure, by which the charges can be completely drained before integration begins (allowing reset operation without kTC noise nor the effect of the previous frame). Consequently, because of lower noise and improved power performance, PPDs dominate the consumer market for silicon-based image sensors. Beyond silicon imaging, incorporating this structure was not possible up until now because of the difficulty of hybridizing two different semiconductor systems.

Now, imec demonstrates successful incorporation of a PPD structure in the readout circuit of thin-film-based image sensors; the first of its kind. A SWIR quantum-dot photodetector was monolithically hybridized with an indium-gallium-zinc oxide (IGZO)-based thin-film transistor into a PPD pixel. This array was subsequently processed on a CMOS readout circuit to form a superior thin-film SWIR image sensor. “The prototype 4T image sensor showed a remarkable low read-out noise of 6.1e-, compared to >100e- for the conventional 3T sensor, demonstrating its superior noise performance” stated Nikolas Papadopoulos, project leader ‘Thin-Film Pinned Photodiode’ at imec. As a result, infrared images can be captured with less noise, distortion or interference, and more accuracy and detail.

---

*The findings are published in the August 2023 edition of NatureElectronics ‘Pinned photodiode for monolithic thin-film image sensors’. Initial results were presented at the 2023 edition of the International Image Sensors Workshop.

@imec_int @NatureElectron #ThinFilm #InfraRed

Change in leadership.

Walter and Peter Kurz have retired from the operational side of the business and take up advisory functions as Chairman and Deputy Chairman of an Advisory Board at thin film and finishing technology enterprise Leonhard Kurz. Dr. Andreas Hirschfelder, previously Senior Vice President of the Business Area Plastic Decoration, becomes the Chief Executive. Dr. Hirschfeld has been with the company for 26 years, working in various roles including as CEO of the subsidiaries PolyIC and BURG DESIGN. Since 2018. A Doctor of Organic Chemistry he has also been responsible for the Business Area Plastic Decoration as Senior Vice President and a Member of the Management Board.

Dr. Andreas Hirschfelder

“I’m delighted by the confidence the Kurz family have placed in me. Continuing the company's success story is both an honor and an incentive – especially in the challenging times we currently live in. But I am convinced that, as an international team, we can meet this challenge and continue to delight our customers in future,” said Dr. Hirschfelder

In a joint statement, Walter and Peter Kurz stated, “We are handing over a highly innovative company that is financially very healthy. We have every confidence that Dr. Andreas Hirschfelder will lead Kurz to continued success.”

Since the early/mid 1970s, Walter and Peter Kurz have developed their family business, which was founded back in 1899, into one of the world’s most successful experts in attractive, functional surface finishing. The decorative, functional layers applied to carrier foil are used in countless everyday products such as cosmetics packaging, wine bottle labels, household devices, and in plastic components for cars. One mainstay is the creation of security features, for example for documents. The Kurz Group is represented in more than 30 locations worldwide and employs over 5,500 people.

In recent years, the Group has consolidated its position as a trailblazer in the sustainable finishing industry. For example, in 2021 Kurz joined the UN Global Compact Network, the world’s largest, most important initiative for sustainable, responsible company management. A comprehensive sustainability report was published in 2022. Their range of products and services is also continually being made more environment- and climate-friendly.

The newly founded Leonhard Kurz Advisory Board will comprise Walter Kurz, Peter Kurz, Andreas Kurz, Dr. Katharina Kurz, Anja Kurz and two external members. This will ensure that the company continues as a family business.

The company Management Board is also being partly reorganized as a result: Thomas Hertlein, previously Executive Vice President of Kurz Transfer Products USA, becomes a Member of the Executive Board of the Group from the beginning of the 2023 fiscal year. Rainer Süßmann succeeds Dr. Hirschfelder as Senior Vice President of the Business Area Plastic Decoration. Both add their strength to that of existing Management Board members Werner Adel, Markus Hoffmann, Ralph Hopfensitz and Dirk Bockwinkel.

 @LEONHARD_KURZ @KURZUSA @PresseBox #PAuto #ThinFilm

Has the printed temperature sensors time come?

Information regarding printed temperature sensors, and indeed about any of the wide variety of printed/flexible sensor technologies, can be found in a recently updated report,  “Printed and Flexible Sensors 2022-2032: Technologies, Players, Markets”.  Technologies covered in the report include printed photodetectors, pressure sensors, gas sensors, capacitive touch sensors, wearable electrodes, and more. Here DTechEx's Dr. Matthew Dyson discusses developments.

Think of a temperature sensor - and a traditional glass thermometer, or perhaps a small thermistor would probably spring to mind. However, a new class of temperature sensors is rapidly emerging that offers spatial resolution together with a thin-film format.

This new class of temperature sensors is made from a solution-processable semiconductor that is coated between conductive rows and columns in a passive matrix architecture. Both the temperature sensing semiconducting layer and the conductors can be printed onto flexible substrates such as PET, enabling low-cost production of a wide range of shapes and sizes.

Why now?
With the ability to provide spatially resolved temperature resolution at a low cost, it might seem surprising that printed temperature sensors are not already widespread. IDTechEx identify two main reasons.

Firstly, existing temperature sensors are cheap, well understood, and very small. While conventional inorganic thermistors or platinum resistive temperature detectors (RTDs) are certainly not flexible, they are generally so small that incorporating them into a component or device doesn’t impose any form factor constraints.

Secondly, thermal diffusion is quite slow. This means that thermal gradients are usually very gentle, certainly when compared to spatial variation in force or light intensity for example. As such, introducing measurement with fine spatial resolution is unnecessary in many cases, since a few thermistors or RTDs embedded in a thermally conductive layer provide equivalent insights.

However, while both of these factors remain true, emerging application areas mean that a combination of spatially resolved temperature measurement, low-cost roll-to-roll (R2R) production, and flexible thin-film format mean that demand for printed temperature sensors is forecast to grow substantially over the next decade, with an increasing number of companies developing this technology.

Battery monitoring for electric vehicles
A forthcoming increase in electric vehicle (EV) adoption is almost unarguable, with multiple governments legislating to ban the sale of internal combustion engines for vehicles at various points in the future. This technological transition is already creating huge opportunities for battery manufacturers.

Thermal management is extremely important for batteries, as anyone who has noticed their smartphone battery life plummet when subjected to heat or cold will attest. Batteries work best within a narrow temperature range, while hot spots can provide an early indication of malfunctions.

Keeping track of battery temperature to adjust heating or cooling as required of course requires temperature sensors. Printed temperature sensors are well suited to this purpose as they are lightweight, thin, cheap to produce in high volumes, offer good thermal contact with pouch cells, and can be laminated together with thin-film heaters to produce an integrated thermal management solution.

Healthcare applications
Printed temperature sensors are also highly promising for healthcare applications. The key attribute here is conformality since printed thin-film sensors can adapt to the curvature of the skin. Indeed, there is growing interest in continuous healthcare monitoring, which will provide extensive opportunities for many types of printed sensors. It involves the continuous tracking of various parameters such as heart rate and temperature to enable remote patient monitoring.

A specific healthcare application currently being explored for printed temperature sensors includes wound monitoring since the healing process is associated with increased blood flow and thus slightly elevated temperatures. The spatial resolution available with printed temperature sensors thus enables the extent of the wound to be tracked over time.

@IDTechEx #PAuto #Automotive #Health

New Head of Optical Coatings Department.

Christian Grunert has been appointed Director of Production for Laser Optics at Laser Components. The 37-year-old engineer succeeds Uwe Schallenberg, who has been working in thin-film coatings since 1977 and served as head of this key department since 2014.

Grunert & Schallenberg

Grunert is not new to the world of dielectric coatings, beam splitters, and mirrors. At university, he focused on lasers and optotechnology. After that, these technologies remained at the center of his professional career. He can draw on more than ten years of experience in the field of optical thin-film technologies – three of them in the R&D department. During this time, he has worked closely with his colleagues from production.

According to CEO Patrick Paul, this internal succession proves the success of close interaction of scientific research and practical implementation, which has always been an integral part of the company philosophy.

@LCGermany #PAuto  

Grant for Thin Film research.

World-leading nanoelectronics research centre imec announces that Kris Myny, one of its young scientists, has been awarded an ERC Starting Grant. The grant of 1.5 million euros is earmarked to open up new research horizons in the field of thin-film transistor technology. This will allow a leap forward compared to current state-of-the-art and enable breakthrough applications in e.g. healthcare and the Internet-of-Things (IoT). ERC Starting Grants are awarded by the European Research Council to support excellent researchers at the stage at which they are starting their own independent research team after a stringent selection procedure; they are among the most prestigious of European research grants.

With his research, Kris Myny wants to realize a breakthrough in thin-film transistor technology, a technology used to create the large-area, flexible circuits that e.g. drive today’s flat-panel displays.
Specifically, he wants to introduce design innovations of unipolar n-type transistor circuits based on amorphous Indium-Gallium-Zinc-Oxide (a-IGZO) as semiconductor. These are currently acknowledged as the most promising transistors for next-generation curved, flexible, or even rollable electronic applications.

Kris Myny

“My goal is to use these transistors to introduce a new logic family for building digital circuits that will drastically decrease the power consumption compared to current flexible circuits. And this of course without compromising the speed of the electronics. At the same time, we will also make the transistors smaller, in a way that is compatible with large-area manufacturing. In addition, I will also look at new techniques to design ultralow-power systems in the new logic style. These will allow building next-generation large-area flexible applications such as displays, IoT sensors, or wearable healthcare sensor patches.”

In a recent press release, the European Commission announced that in 2017 it would invest a record 1.8 billion in its ERC grant scheme. A sizable part of the budget is earmarked for Starting Grants, reserved for young scientists with two to seven years of post-PhD experience. Jo De Boeck, imec’s CTO says “We congratulate Kris Myny for all his valuable research culminating in this grant. Imec goes to great lengths to select and foster our young scientists and provide them with a world-class infrastructure. These ERC Starting Grants show that their work indeed meets the highest standards, comparable to any in Europe.”

@imec_int #thinfilm #Pauto

Good things come in small packages!

Small, accurate and reliable RH and temperature measurement probe!

The Michell PCMini52 relative humidity (RH) and temperature probe provides excellent accuracy and stability in a package that is small yet tough for harsh environments. Widely used for applications including controlled environments, precision manufacturing and meteorology, the instrument comes with a range of options to match usage requirements.

The PCMini52 utilises a thin-film capacitive sensor, designed for extremely fast response and long-term stability for repeatable measurements. The design provides a large capacitive response to small changes in humidity which, in turn, makes the sensor highly sensitive to even small changes in humidity. Digital temperature compensation further ensures excellent device linearity. The PCMini52 electronics are coated in a protective resin to ensure high reliability even in damp and harsh environmental conditions and it has the option of a stainless steel housing for added strength and robustness.

With a miniature space envelope of 80mm in length and 12mm diameter, this versatile probe has a range of output signal options and offers %RH, dew-point, absolute humidity or wet bulb along with temperature readings. The extremely low power consumption of the probe enables it to be used with a battery or for wireless operation if required – ideal for remote applications such as weather stations.

• Marketed in Ireland through Instrument Technology.

Co-operation in thin film PV R&D

Imec and Solliance have announced that imec will be a full partner of Solliance and will integrate its thin film PV R&D efforts in Solliance. With imec as a partner, Solliance aims to be an R&D cluster bringing thin film solar energy technology to excellence.

Solliance works in close cooperation with industry, both to fulfill short-term needs of industry, and to convey promising programs of mid- and long-term research. It focuses on three main thin film technologies: thin film Si, alternatives for CIGS, and organic photovoltaics (OPV). For these principal themes Solliance will collaborate with the industry at its facilities in Eindhoven as well as at imec’s facilities in Leuven, providing direct answers to the industry’s most pressing questions. Solliance also concentrates on generic technologies that will be vital to any thin film PV industry: testing, characterization and monitoring, laser technologies, light management by mechanical texturization, transparent conductive layers, monolithic interconnection, new OPV device development, thin film deposition techniques, sheet-to-sheet processing, roll-to-roll (R2R) processing, and in-line monitoring.

Says Luc Van den hove, President and CEO imec: “The joining of forces in Solliance creates focus and critical mass, needed to be a top level player in the world of thin film PV.” And Hein Willems, Solliance’s managing director: “Strengthened by imec as the fifth member, our research now stretches across the entire field, from fundamentals of materials science to sophisticated production technologies.”  Imec specifically excels in nanoelectronics, and harbors CIGS-related and OPV research teams of significant volume and expertise. It will now continue its thin film R&D within the Solliance cooperation.

Solliance’s ambition is to strengthen the position of the Eindhoven-Leuven-Aachen triangle (ELAT region) as a world player in thin film PV. Solliance now creates synergy among more than 250 researchers with this common goal. Solliance aims to realize this ambition by joint use of state-of-the-art infrastructure, alignment of research programs, and close cooperation with the solar business community. Solliance is amongst others financially supported by the Dutch Province of Brabant.

The announcement is being celebrated at the annual imec booth reception at PVSEC in Hamburg on 7 September at the imec booth, hall B4G booth C11, at 16.30 o’clock.