Semikron

Semikron Danfoss is a family-owned global technology leader in power electronics, specializing in the design, manufacturing, and supply of semiconductor devices, power modules, stacks, and systems for medium to high-power applications.^[1][2] Formed in 2022 through the merger of the German company Semikron—founded in 1951 in Nuremberg by Dr. Friedrich Josef Martin—and Danfoss Silicon Power, a subsidiary of the Danish engineering firm Danfoss, the entity combines over 90 years of expertise to serve industries including e-mobility, renewable energy, industrial drives, and energy storage.^[1][3][4] Headquartered in Nuremberg, Germany, with Danfoss as the majority owner, Semikron Danfoss operates as an independent business unit employing approximately 4,000 people as of 2025 with production facilities in eight countries including Germany, Slovakia, the United States, Italy, China, India, France, and Brazil.^[1][5] The company's product portfolio includes innovative solutions like IGBT and SiC power modules (e.g., SEMITOP, SEMITRANS, and SKiiP series), intelligent power modules, and customized stacks for high-efficiency applications, enabling reduced CO2 emissions in transportation—which accounts for 24% of global emissions—and supporting the transition to sustainable energy systems.^[6][7] Semikron Danfoss emphasizes environmental, social, and governance (ESG) principles, investing heavily in R&D for technologies such as 2kV SiC modules and high-voltage converters to advance electrification and renewable integration.^[8] With a commitment to long-term value creation for stakeholders, the company continues Semikron's legacy of pioneering power semiconductor solutions while leveraging Danfoss's global engineering strengths to address challenges in decarbonization and energy efficiency.^[9][10]

History

Founding and early development

Semikron was founded in 1951 in Nuremberg, Germany, by Dr. Friedrich Josef Martin as a family-owned enterprise specializing in power semiconductor components, particularly rectifiers.^[4][11] The company originated amid Germany's post-World War II economic recovery, with Martin—a student of Ludwig Erhard, the economist behind the "Wirtschaftswunder"—drawing on his expertise to establish a firm focused on innovative semiconductor production in a rebuilding industrial landscape.^[12] In its early years, Semikron concentrated on developing rectifier technologies, achieving a key milestone in 1959 with the production of its first silicon diodes using silicon wafers, though initially limited to a power range of 100 A.^[13] These components targeted industrial applications, including welding equipment, where reliable power conversion was essential.^[14] By 1961, Semikron introduced the world's first avalanche rectifier diode, marking an advancement in high-reliability power semiconductors and solidifying its engineering-driven approach.^[13] The persistent family ownership from the outset cultivated a culture prioritizing technical innovation and quality in mid-20th-century power electronics.^[15]

Global expansion and growth

Semikron began its international expansion in the 1970s with the establishment of its first subsidiary in the United States, marking the company's initial foray into global markets beyond Germany.^[1] This was followed by the opening of a site in China and further diversification with subsidiaries in India and Brazil over the subsequent decades, which facilitated localized production and sales in emerging economies.^[1] By the early 2000s, these efforts had evolved into a network of 25 subsidiaries worldwide, including production facilities in key locations such as Germany, the US, China, India, and Brazil, enabling Semikron to serve diverse industrial sectors efficiently.^[16] Parallel to its geographic growth, Semikron advanced its product portfolio, introducing thyristor modules in the 1970s that became foundational for medium-power applications in industrial drives and power supplies.^[1] In the 1990s, the company introduced insulated gate bipolar transistor (IGBT) modules, which offered improved efficiency and switching performance, scaling production capabilities to cover a power range from 1 kW to 10 MW for applications in renewable energy inverters and electric vehicles.^[1] These innovations positioned Semikron as a leader in power electronics, with ongoing emphasis on research and development investments to enhance reliability and thermal management in semiconductor packaging.^[17] By 2020, Semikron had grown to approximately 3,000 employees globally and achieved annual revenues of around €400 million, reflecting robust demand for its power semiconductor solutions.^[18] Strategic collaborations further bolstered this expansion, including a multi-year partnership with STMicroelectronics initiated around 2018 to integrate silicon carbide (SiC) technology into Semikron's eMPack modules, enhancing performance for high-efficiency electric vehicle applications.^[19] Building on its founding in 1951, these developments solidified Semikron's market positioning in power electronics prior to 2022.^[15]

Merger with Danfoss

On March 29, 2022, Semikron and Danfoss Silicon Power announced their merger to form a joint venture focused on power electronics, with the transaction subject to regulatory approvals in multiple countries.^[20] The merger was finalized on August 22, 2022, less than five months after the announcement, creating Semikron Danfoss as a new entity owned jointly by the Semikron owner-families and the Danfoss Group, with Danfoss holding majority ownership.^[9] The strategic rationale for the merger centered on leveraging complementary strengths to strengthen leadership in power electronics amid growing demand for electrification. Semikron brought deep expertise in power module packaging and innovation, while Danfoss Silicon Power contributed advanced system integration and application knowledge, enabling the combined company to offer end-to-end solutions for key markets.^[20] This partnership, built on over 90 years of combined technology leadership, targeted accelerated growth in renewables, e-mobility, and energy-efficient applications to support global decarbonization efforts.^[9] The merger marked a shift for Semikron from its longstanding family-owned structure to this joint ownership model, while preserving its headquarters in Nuremberg, Germany. Initial outcomes included a combined workforce exceeding 3,500 power electronics specialists across retained production sites in Nuremberg and Flensburg. The expanded portfolio integrated Semikron's module technologies with Danfoss's systems, accompanied by rebranding to Semikron Danfoss and commitments to significant investments in innovation and capacity expansion. In May 2025, Semikron Danfoss signed a memorandum of understanding with CRRC Times Semiconductor to collaborate on chip supply for power modules, enhancing production capabilities.^[9][21]

Corporate operations

Ownership and leadership

Semikron Danfoss operates as a joint venture following the 2022 merger between Semikron and Danfoss Silicon Power, with Danfoss A/S holding a majority stake of 61% and the remaining 39% retained by the founding Semikron families.^[22][23] The company functions as an independent business unit within the Danfoss Group, leveraging the family-owned structures of both parent entities to maintain strategic autonomy while benefiting from group resources.^[9] Leadership is headed by President and CEO Dominic Dorfner, who assumed the role on September 1, 2024, bringing expertise in semiconductor physics with a PhD in the field and prior experience at Voith Turbo and Roland Berger.^[23][24] The board of directors includes representatives from both Danfoss and Semikron, such as Chairman Mika Kulju and former President Claus A. Petersen, who joined the board upon his retirement in 2024 after leading the company since the merger.^[23] Astrid Mozes, President of Danfoss Regions, serves as Chair of Semikron Danfoss Holding A/S, ensuring alignment with broader group objectives.^[25] This structure emphasizes engineering-driven leadership to advance power electronics innovation. Governance blends family-influenced decision-making from the Semikron and Danfoss owner-families with corporate oversight from Danfoss, prioritizing long-term innovation in power semiconductors and modules.^[26][23] The model supports operational independence while integrating into Danfoss' Power Electronics and Drives segment for strategic guidance. Financially, Semikron Danfoss reported annual sales exceeding €1 billion as of 2024, contributing to the segment's €2.447 billion in sales, with profitability supported by strong demand in power module sales despite market volatility in electric vehicles.^[23][25] The segment achieved an operational EBITA margin of 11.3% in 2024, reflecting resilience amid restructuring costs.^[25]

Global facilities and workforce

Semikron Danfoss maintains its headquarters in Nuremberg, Germany, which functions as the central hub for research and development activities as well as administrative operations. This location supports advanced innovation in power electronics, leveraging proximity to key engineering talent and infrastructure in Europe.^[5][1] The company's production network spans multiple continents to ensure a robust global supply chain, with facilities in Germany (including Nuremberg and Flensburg), Slovakia, the United States (Utica, New York), Italy, China, India, France, and Brazil. These more than 10 sites enable localized manufacturing and rapid response to regional demands in the power electronics sector. Some locations, such as the Utica facility, focus on specialized silicon power production, though operations there have seen adjustments amid market shifts in 2025.^{[1][27][28][29]} As of 2025, Semikron Danfoss employs over 4,000 people worldwide, fostering a diverse workforce that draws from multiple nationalities and emphasizes inclusion. The organization aligns with broader Danfoss Group initiatives targeting 30% women in leadership roles by 2025, while investing in employee development through programs like registered apprenticeships in advanced manufacturing and power electronics training.^[5][8][30] Sustainability is embedded in operations across all facilities, with green manufacturing practices such as energy-efficient production lines and CO2 reduction strategies integrated to support the company's commitment to eco-friendly power solutions. These efforts contribute to broader goals of green growth and minimized environmental impact in semiconductor assembly and testing processes.^[1][20]

Products

Discrete semiconductors

Semikron Danfoss produces a range of discrete semiconductors, primarily focusing on standalone diodes and thyristors designed for power control and rectification in industrial applications. These components serve as fundamental building blocks for basic power electronics, enabling efficient energy conversion in devices such as battery chargers, welding equipment, and high-voltage rectifiers. Unlike integrated modules, these discretes are single-device units housed in robust packages to withstand demanding operational conditions.^[31] The product lineup includes discrete rectifier diodes categorized by recovery characteristics: standard (line-frequency) recovery diodes for general rectification, fast recovery diodes for applications requiring quicker turn-off times to minimize switching losses, and avalanche diodes engineered to handle transient overvoltages safely. Discrete thyristors, also known as silicon-controlled rectifiers (SCRs), are offered with standard line-frequency switching characteristics, optimized for high-power on/off control in AC circuits. These thyristors support phase control and are available in configurations suitable for robust industrial use. Representative examples include the SKN series diodes for rectification tasks and the SKKT series thyristors for switching duties. While Semikron's portfolio emphasizes bipolar devices like diodes and thyristors, transistor-based discretes such as MOSFETs are not prominently featured in their standalone offerings, with such technologies more commonly integrated into higher-level modules.^[32][33][34] Technical specifications for these discretes cover a broad spectrum to address low- to high-power needs. Diodes achieve blocking voltages from 200 V to 8000 V and average forward currents up to 11,500 A, with surge current capabilities reaching 100,000 A to manage peak loads effectively. Thyristors similarly span blocking voltages of 600 V to 1800 V, with RMS current ratings from 24 A to 1200 A and peak surge currents up to 25,500 A, enabling high-power switching in demanding environments. Primarily based on silicon for cost-effective performance, these components prioritize reliability through industry-standard designs, though silicon carbide (SiC) variants are explored in related technologies for enhanced efficiency in high-temperature operations. These specifications ensure compatibility with applications requiring precise power handling without excessive losses.^[34][33][14] Semikron Danfoss employs in-house fabrication for advanced bipolar chips used in these discretes, leveraging decades of expertise in semiconductor processing to produce high-quality silicon wafers tailored for power applications. The manufacturing process involves chip production followed by packaging into three primary styles: axial/leaded for PCB mounting in low-power setups, stud-mounted for vibration-resistant installations, and capsule/disc types for high-current, high-voltage scenarios. Each discrete undergoes rigorous production testing, including forward conduction and blocking voltage checks, to verify functionality and ensure compliance with industrial reliability standards. This integrated approach from chip to package enhances consistency and supports long-term durability in harsh environments.^[35][31][36] Historically, Semikron introduced its core discrete semiconductor offerings in the mid-1950s, beginning with selenium-based rectifiers before transitioning to silicon diodes and thyristors as the technology evolved. By the 1970s, disc-type thyristors were developed for DC drives and AC motor controls, marking a shift toward higher-power capabilities. The 1980s saw enhancements with fast thyristors and diodes featuring glass passivation and square chip geometries, reducing switching losses and improving efficiency for modern power systems. These developments have positioned Semikron's discretes as enduring solutions, often serving as foundational elements integrated into more complex power modules for advanced applications.^[13][15]

Power modules

Semikron's power modules integrate multiple discrete semiconductors into compact packages to facilitate efficient power conversion in medium- to high-power applications. These modules serve as essential building blocks, combining devices such as insulated-gate bipolar transistors (IGBTs), silicon carbide (SiC) MOSFETs, thyristors, and diodes to handle demanding electrical loads while minimizing size and improving reliability.^[37] The company's IGBT modules, exemplified by the SEMITRANS series, utilize silicon-based IGBT chips in configurations like half-bridge and sixpack topologies, supporting voltage classes from 600V to 1700V and currents up to 1400A. These modules are housed in robust packages such as SEMITRANS Classic, which include baseplates for effective thermal management, enabling operation in industrial environments with high thermal cycling demands. Thyristor and diode modules, available in the SEMIPACK package, extend capabilities to blocking voltages up to 2200V and currents up to 1360A, often in dual-switch arrangements for rectifier and inverter circuits.^{[38][39][40][41]} SiC MOSFET modules, including the SKiM series, represent a key advancement, offering full or hybrid SiC configurations in sixpack, half-bridge, and buck/boost setups with voltages up to 1700V and currents up to 600A. These modules leverage SiC's superior material properties for faster switching speeds and higher operating temperatures, reducing overall energy losses by up to 50% compared to traditional silicon-based equivalents, which enhances efficiency in power-dense designs. Thermal management is optimized through low-inductance layouts and baseplates, often with direct copper bonding for better heat dissipation.^[42][43] Innovations in Semikron's portfolio include intelligent power modules (IPMs) within the SKiM line, which incorporate integrated gate drivers, protection circuits, and sensors to simplify system design and improve fault tolerance. SiC technology further enables higher power densities, with modules supporting power levels from 1 kW to 10 MW across an extensive range of variants tailored to diverse circuit requirements. This comprehensive selection, encompassing over thousands of options in standard packages, builds on discrete semiconductors to deliver scalable solutions for efficient power handling.^[44][45]

Stacks and systems

Semikron Danfoss offers power stacks and systems as integrated assemblies that combine power modules with essential components such as cooling systems, DC link capacitors, busbars, and control electronics to form ready-to-use solutions for demanding power conversion applications.^[46] These assemblies build upon power modules as core elements, enabling higher-level integration for industrial and mobility sectors.^[47] Key product offerings include the SKS series of power stacks, which provide standardized platforms for diode and thyristor converters as well as IGBT-based systems, supporting current ratings from 180 A to 1500 A RMS and voltages up to 1000 V DC.^[48] Full systems such as the SKAI converters represent complete inverter solutions, particularly for e-mobility, with the SKAI 2 HV platform delivering 50 kW to 500 kW at up to 950 V DC using IGBT technology.^[49] The customization process involves tailored designs through dedicated Stack Centers, where solutions are adapted to specific voltage, current, and environmental requirements, incorporating options for forced-air or liquid cooling (including ShowerPower® technology) and integrated protection circuits for short-circuit, overvoltage, earth fault, and overtemperature events.^[46] This approach leverages Semikron Danfoss's semiconductor and driver expertise to deliver optimized, field-tested assemblies in reduced development timelines.^[47] Advanced features emphasize high power density scalable up to 10 MW, fault-tolerant architectures for enhanced reliability in harsh conditions, and digital interfaces supporting protocols like Modbus, multiple logic levels (0-5 V, 0-12 V, 0-15 V), and up to six PWM signals to enable Industry 4.0 connectivity and modular system expansion.^[46] Development focuses on turnkey systems that facilitate rapid deployment through prequalified designs, easy paralleling, and comprehensive testing for electromagnetic compatibility (EMC) to meet automotive and industrial standards, alongside a targeted mean time between failures (MTBF) exceeding 20 years for long-term operational longevity.^[46]

Applications

Renewable energy

Semikron Danfoss provides advanced power electronics solutions tailored for solar energy applications, including inverters and string optimizers that leverage silicon carbide (SiC) modules to achieve high-efficiency photovoltaic (PV) power conversion. These SiC-based modules, such as the SEMITRANS 20 series, enable reduced switching losses and higher power densities in 1500V DC systems, supporting residential, commercial, and utility-scale installations like SMA's Sunny Central FLEX inverters for large-scale solar projects. In 2025, the company introduced SEMITOP E2 and SEMITRANS 3 modules with 2kV SiC technology, enhancing performance in high-voltage PV systems.^[50][51][52] In wind energy systems, the company offers full-power converters and pitch control systems utilizing insulated gate bipolar transistor (IGBT) stacks, designed for reliable operation in harsh offshore and onshore environments. Products like the SEMISTACK RE provide high IGBT cycling capability and extended capacitor lifetimes, minimizing maintenance for multi-megawatt wind turbine converters, including yaw, pitch drives, and doubly-fed induction generator (DFIG) topologies.^[53][54] For green hydrogen production and utilization, Semikron Danfoss supplies power electronics for electrolyzer systems and fuel cell inverters, incorporating high-voltage thyristor modules to handle demanding AC/DC conversion requirements. The SEMITRANS 10 thyristor-based modules (up to 1400A and 1700V) and SEMITRANS 20 (up to 5MW) support efficient, compact designs in DC-coupled electrolysis setups, while SiC-enhanced inverters facilitate low-loss DC/AC conversion for fuel cells in the kW to MW range, promoting scalable hydrogen infrastructure.^[55][56] Energy storage systems (ESS) benefit from Semikron Danfoss's grid-tie inverters and discrete diode components, which enhance scalability and integration with renewable sources. Discrete diodes integrated into modules like SEMITOP E and SEMiX 3p (up to 956A and 2200V) provide robust protection and rectification, while scalable stacks such as SEMISTACK RE SiC support battery ESS from 8kW to 8MW, enabling efficient grid stabilization and energy management.^[51][32] These renewable energy solutions contribute to the green transition by delivering up to 20% lower losses through advanced topologies and materials, thereby reducing operational costs and improving the economic viability of sustainable power generation installations.^[55][51]

Automotive and e-mobility

Semikron Danfoss plays a pivotal role in advancing electric vehicle (EV) electrification through specialized power electronics tailored for high-reliability applications in passenger cars, commercial vehicles, and infrastructure. The company's solutions emphasize silicon carbide (SiC) and insulated gate bipolar transistor (IGBT) technologies to enhance performance in demanding mobility environments, supporting the transition to sustainable transport systems.^[57][58] In EV traction inverters, Semikron Danfoss offers the eMPack and DCM platforms, which utilize SiC MOSFET modules optimized for 800V systems. The eMPack, available in 2-level and 3-level topologies, supports power outputs from 100 kW to 750 kW with current ratings up to 900 A RMS, featuring low stray inductance of 2.5 nH and double-sided sintering for compact, high-density designs suitable for passenger cars and commercial vehicles.^[59][57] Similarly, the DCM platform accommodates both Si IGBT and SiC MOSFETs at 750 V or 1200 V, enabling scalable inverter solutions from 100 kW to 750 kW with advanced ShowerPower cooling for superior thermal management and efficiency in 400 V and 800 V battery architectures.^[60] These platforms deliver power levels of 400-500 kW in compact footprints, reducing system size while improving overall vehicle range and performance.^[59] For on-board chargers, Semikron Danfoss provides modules such as SEMITOP E and SEMiX 2, supporting AC-DC conversion in the 8-50 kW range, with scalability up to 200 kW for higher-demand applications. These IGBT- and SiC-based designs (650 V to 2000 V) incorporate baseplate-less construction, low inductance, and press-fit pins for enhanced thermal performance and reliability, ensuring compliance with ISO 26262 functional safety standards essential for automotive integration.^[58] Typical configurations handle 11-22 kW outputs, facilitating efficient overnight charging for EVs while minimizing weight and volume.^[61] In heavy-duty transport, Semikron Danfoss delivers liquid-cooled stacks and systems like the SKAI HV series for buses, trucks, and trains, rated up to 500 kVA at 950 V DC using SiC MOSFETs or IGBTs in IP67-rated enclosures. These robust, scalable solutions support power levels approaching 1 MW through paralleling, with features like integrated drivers and sintering for harsh operating conditions in off-highway and rail applications.^[60] The SKAI LV variant extends to lower voltages (up to 96 V DC, 55 kVA) for light-duty electric vehicles, emphasizing modularity and high power cycling capability.^[57] In 2025, new 2kV SiC modules like SEMITRANS 3 were introduced to further improve efficiency in high-voltage e-mobility systems.^[52] Semikron Danfoss also contributes to charging infrastructure with DC fast charger modules, including SEMITRANS Classic and SEMiX 5 using IGBTs (600 V-1700 V), capable of 50-600 kW outputs with support for CCS and CHAdeMO protocols. These solutions enable 350 kW charging stations through scalable topologies and optimized cooling, reducing charge times for high-power EVs and aligning with global standardization efforts.^[58][61] The company's growth in e-mobility is driven by the expanding EV market, where SiC adoption yields significant efficiency improvements in powertrains through reduced switching losses (up to 50% lower in inverters) compared to traditional silicon-based designs, enabling peak efficiencies up to 99.5%.^[57][62] This positions Semikron Danfoss as a key enabler in the projected 25-40% annual increase in electric vehicle sales as of 2025.^[63][64]

Industrial sectors

Semikron Danfoss provides power modules essential for variable frequency drives (VFDs) in industrial motor applications, supporting motors from 0.75 kW to 500 kW.^[65] These modules enable precise speed control, which can reduce energy consumption in applications like pumps and fans compared to fixed-speed operations. The company's SEMiX and SEMITRANS series, featuring IGBT and diode technologies, facilitate efficient power conversion for these drives, enhancing overall system reliability in manufacturing environments. In 2025, advancements like the SEMITRANS 3 with 2kV SiC support higher efficiency in industrial power systems.^[66][52] In welding equipment, Semikron Danfoss employs thyristor-based rectifier modules for arc welding processes, handling currents up to 1000 A.^[40] These SKKD and SKKT series modules, available in SEMIPACK housings, provide robust phase control and rectification for high-current demands in industrial welders.^[14] Their design ensures stable power delivery, minimizing spatter and improving weld quality in metal fabrication.^[67] For uninterruptible power supplies (UPS) and power systems, Semikron Danfoss offers diode and IGBT-based solutions tailored for data centers and critical infrastructure.^[68] These components, such as those in the SEMITRANS and SKiiP lines, support double-conversion topologies with high efficiency and built-in redundancy features like parallel operation for fault tolerance.^[45] This setup ensures continuous power during outages, protecting sensitive equipment in industrial settings.^[39] Semikron Danfoss also supplies customized stacks for other industrial uses, including elevators, cranes, and HVAC systems, where precise control is required.^[69] Integrated power stacks with IGBT modules enable regenerative braking in elevators and cranes, recovering energy during descent or deceleration.^[66] In HVAC applications, these solutions optimize compressor and fan speeds for energy-efficient climate control. To suit harsh industrial environments, Semikron Danfoss products incorporate sector-specific adaptations, such as IP67-rated housings for dust and water resistance in SKAI converters.^[70] Additionally, their modules support integration with programmable logic controllers (PLCs) through compatible interfaces, enabling seamless operation in smart factory automation systems.^[71] These features enhance durability and connectivity in demanding manufacturing processes.^[72]