News: Microelectronics
6 February 2025
Silicon carbide patent activity grows strongly in Q4/2024, reports KnowMade
Technology intelligence and IP strategy consulting company KnowMade says that, for fourth-quarter 2024, its quarterly SiC Patent Monitor shows robust growth, with over 900 new patent families and 400 newly granted patents. This period saw over 100 patents expire or be abandoned and involved seven notable patent transfers.
The industry was also devoid of any new IP litigation in the US or patent opposition in Europe. However, the sector is abuzz with 10 notable patent collaborations and an influx of over 25 IP newcomers entering the field.
Notable innovations and collaborations
Continuous innovation in the SiC industry, particularly in the bulk wafer and bare wafer segment, has led to the emergence of enhanced substrates and reliable power devices, notes KnowMade.
In Q4/2024, for example, NGK Insulators disclosed a composite SiC substrate with a biaxially oriented SiC layer that helps to reduce warpage by controlling a Raman shift value and to prevent breaking and cracking in the substrate during processing by controlling the volume density of base plane dislocations (BDP).
Another notable player in the quarter is SICC, which published inventions improving 3D stress distribution and reducing internal stress in large-diameter (>150mm) SiC wafers.
Sumitomo Electric continues to lead IP activities in the epitaxial wafer segment, with four new inventions disclosed during Q4/2024. One new invention relates to issues in the epitaxial reactor, such as the presence of SiC particles on the susceptor, causing recesses in the rear surface of SiC epiwafers. Another invention focuses on the reduction of certain defects (bump, pit, carrot, triangular defect, downfall) that can be imaged using a confocal scanning device. Another invention is more closely related to device reliability and aims to improve recombination efficiency while reducing the required thickness of SiC epilayers, in order to prevent stacking faults from transferring from the buffer layer to the drift layer.
In the device segment, among the patenting activity of several Chinese automotive players such as NIO and FAW, NIO stands out with a European patent publication related to SiC trench MOSFETs. Other players in the automotive supply chain that have been actively filing patents during Q4/2024 include Bosch (e.g. to improve the short-circuit robustness of SiC FETs) and Nexperia (e.g. to improve on-resistance and surge performance of SiC Schotty diodes).
In the module and packaging segment, onsemi has disclosed electroless plating methods and systems suitable for SiC devices. Also, Mitsubishi Electric is still present with two new inventions, including one to suppress heat occurring in a SiC MOSFET connected in parallel with a Si IGBT, without providing a temperature detection circuit and a current detection circuit. Furthermore, Navitas Semiconductor, a leading player in the power GaN market, aims to strengthen its patent portfolio for power SiC with a new invention that provides balanced current flow in SiC power modules.
In the circuits and applications segment, ZF is also continuing tom play its part, with a method of driving parallel-connected SiC MOSFETs and Si IGBTs based on the rapid detection of the current load of the active (switched-on) device. Furthermore, a collaboration between BMW and CSA Catapult and the University of Warwick in the UK has led to a new patent publication describing a monitoring device to measure the temperature or current in SiC devices under high current load even under harsh mechanical conditions (e.g. strong vibration, in automotive applications etc).
KnowMade concludes that this is one of the noteworthy collaborations highlighting the strategic alliances that are essential for maintaining technological leadership and fostering innovation.
Silicon carbide patent analysis shows firms building vertically integrated supply chains
