Atomic Layer Deposition (ALD) enables the scaling of logic and memory semiconductor devices and is currently experiencing rapid adoption in specialty device fabrication, such as for wide-bandgap power semiconductors. Electronics industry experts and researchers will offer insights into ALD trends and adoption at Beneq ALD TechDay at SEMICON Europa 2023, Nov. 14-17 in Munich, Germany. SEMI spoke with Taguhi Yeghoyan, Senior Technology and Market Analyst, Semiconductor Manufacturing and Equipment at Yole Intelligence; Alexander Perros, Head of Process Development, Semiconductor ALD of Beneq; and Niels Posthuma, Principal Engineer, GaN Power Electronics at imec.
The three industry experts shared their views on ALD’s applicability in rising specialty device markets ahead of their SEMICON Europa talks on November 14, 2023. Join us at the event to meet key industry influencers. Register your interest.
SEMI: Is device miniaturization driving the adoption of ALD high-k dielectrics in the More-than-Moore semiconductor markets? This was the case with advanced logic and memory chip production. What other factors also contribute to wafer fab adoption?
Posthuma: For GaN power electronic devices such as p-GaN gate High Electron Mobility Transistors or (semi)-vertical GaN MOSFETs, the adoption of ALD dielectrics is mainly driven by the quality of surface passivation and the bulk properties of the dielectric. It is really driven by the requirements of the GaN power device application itself, not by miniaturization.
Yeghoyan: I agree with Niels. In the More-than-Moore device area, the primary reason for ALD adoption is surface passivation. This is true at the front end, for example for GaN transistors, but also at the back end, for example for photonics devices. Nevertheless, usage of ALD for miniaturization is seen for CMOS Image Sensor production and Advanced Packaging.
Perros: I agree with Niels and Taguhi in that surface passivation is the main driver for ALD adoption for power electronics. I would add that ALD’s ability to apply a high quality conformal and uniform coating over different types of topographies is another major driver. Miniaturization is not a main driver, per se, but we have encountered plenty of cases where ALD is a uniquely suitable solution. This is thanks to the small dimensions and aspect ratios of some structures, for example in uLED and RF devices.
SEMI: What are currently the most common ALD process solutions (for instance, PEALD with AlN, SiNx) for addressing the interfacial layer and surface passivation challenges faced by More-than-Moore semiconductors?
Posthuma: For GaN power transistors, thermal ALD Al2O3, AlON and possibly AlN are important for good surface passivation of the access region on AlGaN in p-GaN gate HEMTs or in the gate area of (semi)-vertical MOSFET devices.
Yeghoyan: Indeed, it is true for the front-end processing of power devices. Moreover, for the overall device passivation, SiNx and Al2O3 are used.
Perros: Looking forward, SiO2 appears to be the ALD process solution for SiC power electronics. It is also useful to highlight the important passivation role in-situ pre-treatments for some applications such as GaN power electronic devices.
SEMI: GaN technologies have become a key inflection point for ALD wafer fab equipment, across Power, RF, and µLED markets. In your opinion, what is the performance enhancement of ALD solutions versus alternatives, and how will that evolve over the next two to three years?
Posthuma: ALD solutions offer high quality interface layers for surface passivation or as gate dielectrics, essential for low dynamic switching losses and hysteresis effects. ALD technology is outperforming in terms of final device performance compared to classical PECVD dielectric layers, for example.
In the future, we expect further optimization of the ALD deposition conditions and implementation of in-situ surface pre-treatments can help to further improve the device performance both in static and dynamic conditions and also improve the stability and reliability of GaN power electronic devices.
Yeghoyan: Again, Niels’ answer is excellent. GaN will be adopted in consumer as well as other end markets, such as automotive/transportation, energy or industrial, with high double digit CAGR.
While for the consumer end market, the most important aspect is device performance; for the other end markets, device reliability and longevity are equally important. Since ALD improves both device performance and reliability, we can be certain that ALD adoption will continue.
Perros: Excellent points by Niels and Taguhi. ALD performance enhancement will be driven through the optimization of existing and upcoming ALD solutions for their respective applications. This optimization is in turn driven through greater understanding of process parameters on material properties. The latter poses a challenge for tool vendors to provide a platform that supports ALD film tuneability and control, particularly for plasma-enhanced ALD, while meeting other requirements such as productivity.
SEMI: Who should attend the event?
Perros: The ALD TechDay is particularly relevant for three categories of experts:
- Integrated device manufacturers (IDM)
- Foundries
- Research and technology organizations (RTO)
Professionals involved in specialty semiconductor devices and the device markets, such as the following, should also attend:
- Advanced packaging
- CMOS image sensors
- Optoelectronics, µLED and photonics devices
- Power devices (GaN and SiC)
- Radio frequency devices
- µOLED
We look forward to welcoming you at the ALD TechDay virtual panel!
Taguhi Yeghoyan is Senior Technology and Market Analyst, Semiconductor Manufacturing and Equipment at Yole Intelligence. Based on her expertise in semiconductor supply chain (processes, materials, equipment, and related applications), Taguhi performs technology and market reports and is engaged in relevant custom projects. Prior to Yole, she worked in world-class European research centers and laboratories, including imec and CEA Leti.
Alexander Perros is Head of Process Development, Semiconductor ALD, at Beneq. Alexander possesses extensive knowledge of atomic layer deposition, equipment, process integration, and technologies. Prior to Beneq, he held several roles, including principle engineer for the semiconductor contract manufacturer Summa Semiconductor, GM and co-Founder of Nanovate, and other positions in academia centered around the commercialization of research results.
Niels Posthuma is Principal Engineer, GaN Power Electronics at imec. Niels begun his Ph.D. at imec in 2000, and received his doctorate on germanium photovoltaic devices from the Catholic University of Leuven in 2006. Since then, Niels’ work covered the development of high-efficiency silicon solar cells and the development of GaN-based power transistors, with focus on p-GaN gate HEMTs for various voltage range applications.
Serena Brischetto is Director of Marketing and Digital Engagement at SEMI Europe.